diff options
Diffstat (limited to 'Lib/csv.py')
| -rw-r--r-- | Lib/csv.py | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/Lib/csv.py b/Lib/csv.py index ff51a86484..984ed7e581 100644 --- a/Lib/csv.py +++ b/Lib/csv.py @@ -132,6 +132,10 @@ class DictWriter: self.extrasaction = extrasaction self.writer = writer(f, dialect, *args, **kwds) + def writeheader(self): + header = dict(zip(self.fieldnames, self.fieldnames)) + self.writerow(header) + def _dict_to_list(self, rowdict): if self.extrasaction == "raise": wrong_fields = [k for k in rowdict if k not in self.fieldnames] @@ -170,7 +174,7 @@ class Sniffer: Returns a dialect (or None) corresponding to the sample """ - quotechar, delimiter, skipinitialspace = \ + quotechar, doublequote, delimiter, skipinitialspace = \ self._guess_quote_and_delimiter(sample, delimiters) if not delimiter: delimiter, skipinitialspace = self._guess_delimiter(sample, @@ -184,8 +188,8 @@ class Sniffer: lineterminator = '\r\n' quoting = QUOTE_MINIMAL # escapechar = '' - doublequote = False + dialect.doublequote = doublequote dialect.delimiter = delimiter # _csv.reader won't accept a quotechar of '' dialect.quotechar = quotechar or '"' @@ -217,8 +221,8 @@ class Sniffer: break if not matches: - return ('', None, 0) # (quotechar, delimiter, skipinitialspace) - + # (quotechar, doublequote, delimiter, skipinitialspace) + return ('', False, None, 0) quotes = {} delims = {} spaces = 0 @@ -255,7 +259,19 @@ class Sniffer: delim = '' skipinitialspace = 0 - return (quotechar, delim, skipinitialspace) + # if we see an extra quote between delimiters, we've got a + # double quoted format + dq_regexp = re.compile(r"((%(delim)s)|^)\W*%(quote)s[^%(delim)s\n]*%(quote)s[^%(delim)s\n]*%(quote)s\W*((%(delim)s)|$)" % \ + {'delim':delim, 'quote':quotechar}, re.MULTILINE) + + + + if dq_regexp.search(data): + doublequote = True + else: + doublequote = False + + return (quotechar, doublequote, delim, skipinitialspace) def _guess_delimiter(self, data, delimiters): @@ -265,7 +281,7 @@ class Sniffer: an all or nothing approach, so we allow for small variations in this number. 1) build a table of the frequency of each character on every line. - 2) build a table of freqencies of this frequency (meta-frequency?), + 2) build a table of frequencies of this frequency (meta-frequency?), e.g. 'x occurred 5 times in 10 rows, 6 times in 1000 rows, 7 times in 2 rows' 3) use the mode of the meta-frequency to determine the /expected/ |