Mercurial > cpython-lru_cache-weakref

annotate Lib/csv.py @ 48715:48dddfd2fbf3

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RPC_WSTR is not available Visual Studio 2003 or earlier. (Maybe I should have defined RPC_WSTR on old compiler, but uuidcreate() is only place using it, so I simply replaced with unsigned short *)
author Hirokazu Yamamoto <ocean-city@m2.ccsnet.ne.jp>
date Sun, 17 Aug 2008 07:26:26 +0000
parents 1a11717a154b
children edb5a8593749
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1
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2 """
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3 csv.py - read/write/investigate CSV files
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4 """
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5
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6 import re
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7 from _csv import Error, __version__, writer, reader, register_dialect, \
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8 unregister_dialect, get_dialect, list_dialects, \
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9 field_size_limit, \
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10 QUOTE_MINIMAL, QUOTE_ALL, QUOTE_NONNUMERIC, QUOTE_NONE, \
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11 __doc__
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12 from _csv import Dialect as _Dialect
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13
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14 from io import StringIO
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15
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16 __all__ = [ "QUOTE_MINIMAL", "QUOTE_ALL", "QUOTE_NONNUMERIC", "QUOTE_NONE",
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17 "Error", "Dialect", "excel", "excel_tab", "reader", "writer",
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18 "register_dialect", "get_dialect", "list_dialects", "Sniffer",
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19 "unregister_dialect", "__version__", "DictReader", "DictWriter" ]
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20
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21 class Dialect:
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22 """Describe an Excel dialect.
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23
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24 This must be subclassed (see csv.excel). Valid attributes are:
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25 delimiter, quotechar, escapechar, doublequote, skipinitialspace,
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26 lineterminator, quoting.
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27
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28 """
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29 _name = ""
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30 _valid = False
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31 # placeholders
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32 delimiter = None
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33 quotechar = None
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34 escapechar = None
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35 doublequote = None
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36 skipinitialspace = None
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37 lineterminator = None
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38 quoting = None
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39
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40 def __init__(self):
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41 if self.__class__ != Dialect:
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42 self._valid = True
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43 self._validate()
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44
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45 def _validate(self):
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46 try:
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47 _Dialect(self)
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48 except TypeError as e:
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49 # We do this for compatibility with py2.3
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50 raise Error(str(e))
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51
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52 class excel(Dialect):
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53 """Describe the usual properties of Excel-generated CSV files."""
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54 delimiter = ','
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55 quotechar = '"'
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56 doublequote = True
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57 skipinitialspace = False
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58 lineterminator = '\r\n'
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59 quoting = QUOTE_MINIMAL
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60 register_dialect("excel", excel)
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61
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62 class excel_tab(excel):
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63 """Describe the usual properties of Excel-generated TAB-delimited files."""
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64 delimiter = '\t'
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65 register_dialect("excel-tab", excel_tab)
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66
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67
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68 class DictReader:
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69 def __init__(self, f, fieldnames=None, restkey=None, restval=None,
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70 dialect="excel", *args, **kwds):
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71 self._fieldnames = fieldnames # list of keys for the dict
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72 self.restkey = restkey # key to catch long rows
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73 self.restval = restval # default value for short rows
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74 self.reader = reader(f, dialect, *args, **kwds)
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75 self.dialect = dialect
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76 self.line_num = 0
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77
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78 def __iter__(self):
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79 return self
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80
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81 @property
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82 def fieldnames(self):
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83 if self._fieldnames is None:
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84 try:
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85 self._fieldnames = next(self.reader)
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86 except StopIteration:
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87 pass
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88 self.line_num = self.reader.line_num
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89 return self._fieldnames
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90
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91 @fieldnames.setter
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92 def fieldnames(self, value):
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93 self._fieldnames = value
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94
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95 def __next__(self):
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96 if self.line_num == 0:
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97 # Used only for its side effect.
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98 self.fieldnames
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99 row = next(self.reader)
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100 self.line_num = self.reader.line_num
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101
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102 # unlike the basic reader, we prefer not to return blanks,
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103 # because we will typically wind up with a dict full of None
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104 # values
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105 while row == []:
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106 row = next(self.reader)
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107 d = dict(zip(self.fieldnames, row))
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108 lf = len(self.fieldnames)
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109 lr = len(row)
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110 if lf < lr:
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111 d[self.restkey] = row[lf:]
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112 elif lf > lr:
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113 for key in self.fieldnames[lr:]:
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114 d[key] = self.restval
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115 return d
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116
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117
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118 class DictWriter:
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119 def __init__(self, f, fieldnames, restval="", extrasaction="raise",
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120 dialect="excel", *args, **kwds):
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121 self.fieldnames = fieldnames # list of keys for the dict
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122 self.restval = restval # for writing short dicts
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123 if extrasaction.lower() not in ("raise", "ignore"):
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124 raise ValueError("extrasaction (%s) must be 'raise' or 'ignore'"
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125 % extrasaction)
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126 self.extrasaction = extrasaction
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127 self.writer = writer(f, dialect, *args, **kwds)
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128
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129 def _dict_to_list(self, rowdict):
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130 if self.extrasaction == "raise":
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131 wrong_fields = [k for k in rowdict if k not in self.fieldnames]
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132 if wrong_fields:
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133 raise ValueError("dict contains fields not in fieldnames: "
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134 + ", ".join(wrong_fields))
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135 return [rowdict.get(key, self.restval) for key in self.fieldnames]
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136
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137 def writerow(self, rowdict):
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138 return self.writer.writerow(self._dict_to_list(rowdict))
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139
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140 def writerows(self, rowdicts):
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141 rows = []
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142 for rowdict in rowdicts:
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143 rows.append(self._dict_to_list(rowdict))
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144 return self.writer.writerows(rows)
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145
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146 # Guard Sniffer's type checking against builds that exclude complex()
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147 try:
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148 complex
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149 except NameError:
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150 complex = float
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151
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152 class Sniffer:
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153 '''
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154 "Sniffs" the format of a CSV file (i.e. delimiter, quotechar)
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155 Returns a Dialect object.
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156 '''
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157 def __init__(self):
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158 # in case there is more than one possible delimiter
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159 self.preferred = [',', '\t', ';', ' ', ':']
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160
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161
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162 def sniff(self, sample, delimiters=None):
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163 """
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164 Returns a dialect (or None) corresponding to the sample
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165 """
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166
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167 quotechar, delimiter, skipinitialspace = \
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168 self._guess_quote_and_delimiter(sample, delimiters)
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96eb2a5cfbef Fix a delimiter detection problem in sniffer. Sniffing "a|b|c\r\n" was
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169 if not delimiter:
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170 delimiter, skipinitialspace = self._guess_delimiter(sample,
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171 delimiters)
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172
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parents: 36146
diff changeset
173 if not delimiter:
43020
907a45df1295 Raise statement normalization in Lib/.
Collin Winter <collinw@gmail.com>
parents: 42142
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174 raise Error("Could not determine delimiter")
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175
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176 class dialect(Dialect):
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177 _name = "sniffed"
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178 lineterminator = '\r\n'
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2fad548391de Attempt to deal with some obvious errors in the code. These were all
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179 quoting = QUOTE_MINIMAL
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180 # escapechar = ''
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181 doublequote = False
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182
28828
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diff changeset
183 dialect.delimiter = delimiter
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diff changeset
184 # _csv.reader won't accept a quotechar of ''
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diff changeset
185 dialect.quotechar = quotechar or '"'
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parents: 28825
diff changeset
186 dialect.skipinitialspace = skipinitialspace
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187
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188 return dialect
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189
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190
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191 def _guess_quote_and_delimiter(self, data, delimiters):
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192 """
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193 Looks for text enclosed between two identical quotes
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194 (the probable quotechar) which are preceded and followed
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195 by the same character (the probable delimiter).
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196 For example:
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197 ,'some text',
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198 The quote with the most wins, same with the delimiter.
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199 If there is no quotechar the delimiter can't be determined
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200 this way.
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201 """
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202
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203 matches = []
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204 for restr in ('(?P<delim>[^\w\n"\'])(?P<space> ?)(?P<quote>["\']).*?(?P=quote)(?P=delim)', # ,".*?",
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205 '(?:^|\n)(?P<quote>["\']).*?(?P=quote)(?P<delim>[^\w\n"\'])(?P<space> ?)', # ".*?",
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206 '(?P<delim>>[^\w\n"\'])(?P<space> ?)(?P<quote>["\']).*?(?P=quote)(?:$|\n)', # ,".*?"
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207 '(?:^|\n)(?P<quote>["\']).*?(?P=quote)(?:$|\n)'): # ".*?" (no delim, no space)
30292
79b1a9ec5223 use the long names for re compilation options; this makes it easier to
Fred Drake <fdrake@acm.org>
parents: 29422
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208 regexp = re.compile(restr, re.DOTALL | re.MULTILINE)
28804
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209 matches = regexp.findall(data)
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210 if matches:
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211 break
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212
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213 if not matches:
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214 return ('', None, 0) # (quotechar, delimiter, skipinitialspace)
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215
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216 quotes = {}
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217 delims = {}
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218 spaces = 0
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219 for m in matches:
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220 n = regexp.groupindex['quote'] - 1
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221 key = m[n]
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222 if key:
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223 quotes[key] = quotes.get(key, 0) + 1
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224 try:
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225 n = regexp.groupindex['delim'] - 1
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226 key = m[n]
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227 except KeyError:
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228 continue
29169
434ef174f478 * Correct Sniffer doc to correspond to the implementation.
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diff changeset
229 if key and (delimiters is None or key in delimiters):
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230 delims[key] = delims.get(key, 0) + 1
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231 try:
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232 n = regexp.groupindex['space'] - 1
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233 except KeyError:
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234 continue
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235 if m[n]:
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236 spaces += 1
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237
39627
e86c0b29b4a2 Kill reduce(). A coproduction of John Reese, Jacques Frechet, and Alex M.
Guido van Rossum <guido@python.org>
parents: 36157
diff changeset
238 quotechar = max(quotes, key=quotes.get)
28804
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239
0c950e3323ee cvs is going to be a module again
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240 if delims:
39627
e86c0b29b4a2 Kill reduce(). A coproduction of John Reese, Jacques Frechet, and Alex M.
Guido van Rossum <guido@python.org>
parents: 36157
diff changeset
241 delim = max(delims, key=delims.get)
28804
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242 skipinitialspace = delims[delim] == spaces
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243 if delim == '\n': # most likely a file with a single column
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244 delim = ''
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245 else:
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246 # there is *no* delimiter, it's a single column of quoted data
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247 delim = ''
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248 skipinitialspace = 0
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249
0c950e3323ee cvs is going to be a module again
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diff changeset
250 return (quotechar, delim, skipinitialspace)
0c950e3323ee cvs is going to be a module again
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251
0c950e3323ee cvs is going to be a module again
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diff changeset
252
29169
434ef174f478 * Correct Sniffer doc to correspond to the implementation.
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diff changeset
253 def _guess_delimiter(self, data, delimiters):
28804
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254 """
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255 The delimiter /should/ occur the same number of times on
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parents:
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256 each row. However, due to malformed data, it may not. We don't want
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257 an all or nothing approach, so we allow for small variations in this
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258 number.
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259 1) build a table of the frequency of each character on every line.
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260 2) build a table of freqencies of this frequency (meta-frequency?),
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261 e.g. 'x occurred 5 times in 10 rows, 6 times in 1000 rows,
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262 7 times in 2 rows'
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263 3) use the mode of the meta-frequency to determine the /expected/
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264 frequency for that character
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265 4) find out how often the character actually meets that goal
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266 5) the character that best meets its goal is the delimiter
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267 For performance reasons, the data is evaluated in chunks, so it can
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268 try and evaluate the smallest portion of the data possible, evaluating
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269 additional chunks as necessary.
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270 """
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271
42142
a53e48be6df9 Merged revisions 56125-56153 via svnmerge from
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diff changeset
272 data = list(filter(None, data.split('\n')))
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273
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274 ascii = [chr(c) for c in range(127)] # 7-bit ASCII
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275
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276 # build frequency tables
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277 chunkLength = min(10, len(data))
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278 iteration = 0
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279 charFrequency = {}
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280 modes = {}
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281 delims = {}
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282 start, end = 0, min(chunkLength, len(data))
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283 while start < len(data):
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284 iteration += 1
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285 for line in data[start:end]:
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parents:
diff changeset
286 for char in ascii:
28828
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parents: 28825
diff changeset
287 metaFrequency = charFrequency.get(char, {})
28804
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288 # must count even if frequency is 0
36146
22dbf5818b0b Fix for problem with Sniffer class. If your delimiter is whitespace and the
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parents: 34406
diff changeset
289 freq = line.count(char)
28804
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290 # value is the mode
28828
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parents: 28825
diff changeset
291 metaFrequency[freq] = metaFrequency.get(freq, 0) + 1
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diff changeset
292 charFrequency[char] = metaFrequency
28804
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parents:
diff changeset
293
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
294 for char in charFrequency.keys():
40809
f340cb045bf9 - PEP 3106: dict.iterkeys(), .iteritems(), .itervalues() are now gone;
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parents: 40644
diff changeset
295 items = list(charFrequency[char].items())
28804
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diff changeset
296 if len(items) == 1 and items[0][0] == 0:
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parents:
diff changeset
297 continue
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
298 # get the mode of the frequencies
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
299 if len(items) > 1:
39627
e86c0b29b4a2 Kill reduce(). A coproduction of John Reese, Jacques Frechet, and Alex M.
Guido van Rossum <guido@python.org>
parents: 36157
diff changeset
300 modes[char] = max(items, key=lambda x: x[1])
28804
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parents:
diff changeset
301 # adjust the mode - subtract the sum of all
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
302 # other frequencies
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
303 items.remove(modes[char])
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parents:
diff changeset
304 modes[char] = (modes[char][0], modes[char][1]
39627
e86c0b29b4a2 Kill reduce(). A coproduction of John Reese, Jacques Frechet, and Alex M.
Guido van Rossum <guido@python.org>
parents: 36157
diff changeset
305 - sum(item[1] for item in items))
28804
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306 else:
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parents:
diff changeset
307 modes[char] = items[0]
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
308
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
309 # build a list of possible delimiters
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diff changeset
310 modeList = modes.items()
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
311 total = float(chunkLength * iteration)
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parents:
diff changeset
312 # (rows of consistent data) / (number of rows) = 100%
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313 consistency = 1.0
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
314 # minimum consistency threshold
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diff changeset
315 threshold = 0.9
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parents:
diff changeset
316 while len(delims) == 0 and consistency >= threshold:
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parents:
diff changeset
317 for k, v in modeList:
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parents:
diff changeset
318 if v[0] > 0 and v[1] > 0:
29169
434ef174f478 * Correct Sniffer doc to correspond to the implementation.
Skip Montanaro <skip@pobox.com>
parents: 28828
diff changeset
319 if ((v[1]/total) >= consistency and
434ef174f478 * Correct Sniffer doc to correspond to the implementation.
Skip Montanaro <skip@pobox.com>
parents: 28828
diff changeset
320 (delimiters is None or k in delimiters)):
28804
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diff changeset
321 delims[k] = v
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
322 consistency -= 0.01
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
323
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
324 if len(delims) == 1:
40809
f340cb045bf9 - PEP 3106: dict.iterkeys(), .iteritems(), .itervalues() are now gone;
Guido van Rossum <guido@python.org>
parents: 40644
diff changeset
325 delim = list(delims.keys())[0]
28804
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diff changeset
326 skipinitialspace = (data[0].count(delim) ==
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
327 data[0].count("%c " % delim))
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
328 return (delim, skipinitialspace)
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
329
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
330 # analyze another chunkLength lines
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
331 start = end
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
332 end += chunkLength
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
333
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
334 if not delims:
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
335 return ('', 0)
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
336
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
337 # if there's more than one, fall back to a 'preferred' list
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
338 if len(delims) > 1:
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
339 for d in self.preferred:
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
340 if d in delims.keys():
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
341 skipinitialspace = (data[0].count(d) ==
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
342 data[0].count("%c " % d))
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
343 return (d, skipinitialspace)
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
344
36157
96eb2a5cfbef Fix a delimiter detection problem in sniffer. Sniffing "a|b|c\r\n" was
Skip Montanaro <skip@pobox.com>
parents: 36146
diff changeset
345 # nothing else indicates a preference, pick the character that
96eb2a5cfbef Fix a delimiter detection problem in sniffer. Sniffing "a|b|c\r\n" was
Skip Montanaro <skip@pobox.com>
parents: 36146
diff changeset
346 # dominates(?)
96eb2a5cfbef Fix a delimiter detection problem in sniffer. Sniffing "a|b|c\r\n" was
Skip Montanaro <skip@pobox.com>
parents: 36146
diff changeset
347 items = [(v,k) for (k,v) in delims.items()]
96eb2a5cfbef Fix a delimiter detection problem in sniffer. Sniffing "a|b|c\r\n" was
Skip Montanaro <skip@pobox.com>
parents: 36146
diff changeset
348 items.sort()
96eb2a5cfbef Fix a delimiter detection problem in sniffer. Sniffing "a|b|c\r\n" was
Skip Montanaro <skip@pobox.com>
parents: 36146
diff changeset
349 delim = items[-1][1]
96eb2a5cfbef Fix a delimiter detection problem in sniffer. Sniffing "a|b|c\r\n" was
Skip Montanaro <skip@pobox.com>
parents: 36146
diff changeset
350
28804
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parents:
diff changeset
351 skipinitialspace = (data[0].count(delim) ==
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
352 data[0].count("%c " % delim))
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
353 return (delim, skipinitialspace)
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
354
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
355
28828
b37af21b77be rework Sniffer api significantly
Skip Montanaro <skip@pobox.com>
parents: 28825
diff changeset
356 def has_header(self, sample):
28804
0c950e3323ee cvs is going to be a module again
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357 # Creates a dictionary of types of data in each column. If any
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
358 # column is of a single type (say, integers), *except* for the first
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
359 # row, then the first row is presumed to be labels. If the type
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
360 # can't be determined, it is assumed to be a string in which case
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
361 # the length of the string is the determining factor: if all of the
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
362 # rows except for the first are the same length, it's a header.
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
363 # Finally, a 'vote' is taken at the end for each column, adding or
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
364 # subtracting from the likelihood of the first row being a header.
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
365
28828
b37af21b77be rework Sniffer api significantly
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parents: 28825
diff changeset
366 rdr = reader(StringIO(sample), self.sniff(sample))
28804
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
367
41501
0c5019afc55b PEP 3114: rename .next() to .__next__() and add next() builtin.
Georg Brandl <georg@python.org>
parents: 40809
diff changeset
368 header = next(rdr) # assume first row is header
28804
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
369
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
370 columns = len(header)
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
371 columnTypes = {}
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
372 for i in range(columns): columnTypes[i] = None
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
373
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
374 checked = 0
28828
b37af21b77be rework Sniffer api significantly
Skip Montanaro <skip@pobox.com>
parents: 28825
diff changeset
375 for row in rdr:
28804
0c950e3323ee cvs is going to be a module again
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parents:
diff changeset
376 # arbitrary number of rows to check, to keep it sane
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
377 if checked > 20:
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
378 break
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
379 checked += 1
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
380
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
381 if len(row) != columns:
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
382 continue # skip rows that have irregular number of columns
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
383
40809
f340cb045bf9 - PEP 3106: dict.iterkeys(), .iteritems(), .itervalues() are now gone;
Guido van Rossum <guido@python.org>
parents: 40644
diff changeset
384 for col in list(columnTypes.keys()):
29411
bac2c0e7c20a SF Patch #744104: Remove eval() from csv
Raymond Hettinger <python@rcn.com>
parents: 29169
diff changeset
385
46548
85d4671565c8 Obvious simplification, now that "long" has disappeared.
Amaury Forgeot d'Arc <amauryfa@gmail.com>
parents: 45996
diff changeset
386 for thisType in [int, float, complex]:
28804
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
387 try:
29411
bac2c0e7c20a SF Patch #744104: Remove eval() from csv
Raymond Hettinger <python@rcn.com>
parents: 29169
diff changeset
388 thisType(row[col])
bac2c0e7c20a SF Patch #744104: Remove eval() from csv
Raymond Hettinger <python@rcn.com>
parents: 29169
diff changeset
389 break
29420
f87fcd0870bf The multiple exception catch should be in a tuple.
Raymond Hettinger <python@rcn.com>
parents: 29411
diff changeset
390 except (ValueError, OverflowError):
29411
bac2c0e7c20a SF Patch #744104: Remove eval() from csv
Raymond Hettinger <python@rcn.com>
parents: 29169
diff changeset
391 pass
bac2c0e7c20a SF Patch #744104: Remove eval() from csv
Raymond Hettinger <python@rcn.com>
parents: 29169
diff changeset
392 else:
28804
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
393 # fallback to length of string
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
394 thisType = len(row[col])
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
395
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
396 if thisType != columnTypes[col]:
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
397 if columnTypes[col] is None: # add new column type
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
398 columnTypes[col] = thisType
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
399 else:
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
400 # type is inconsistent, remove column from
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
401 # consideration
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
402 del columnTypes[col]
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
403
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
404 # finally, compare results against first row and "vote"
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
405 # on whether it's a header
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
406 hasHeader = 0
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
407 for col, colType in columnTypes.items():
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
408 if type(colType) == type(0): # it's a length
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
409 if len(header[col]) != colType:
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
410 hasHeader += 1
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
411 else:
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
412 hasHeader -= 1
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
413 else: # attempt typecast
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
414 try:
29411
bac2c0e7c20a SF Patch #744104: Remove eval() from csv
Raymond Hettinger <python@rcn.com>
parents: 29169
diff changeset
415 colType(header[col])
29422
cf8ae3b0dcdc One more multiple exception catch should be in a tuple.
Raymond Hettinger <python@rcn.com>
parents: 29420
diff changeset
416 except (ValueError, TypeError):
28804
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
417 hasHeader += 1
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
418 else:
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
419 hasHeader -= 1
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
420
0c950e3323ee cvs is going to be a module again
Skip Montanaro <skip@pobox.com>
parents:
diff changeset
421 return hasHeader > 0