diff options
Diffstat (limited to 'Lib/csv.py')
| -rw-r--r-- | Lib/csv.py | 67 |
1 files changed, 32 insertions, 35 deletions
diff --git a/Lib/csv.py b/Lib/csv.py index 984ed7e581b..8dfc77e3108 100644 --- a/Lib/csv.py +++ b/Lib/csv.py @@ -4,7 +4,6 @@ csv.py - read/write/investigate CSV files """ import re -from functools import reduce from _csv import Error, __version__, writer, reader, register_dialect, \ unregister_dialect, get_dialect, list_dialects, \ field_size_limit, \ @@ -12,10 +11,7 @@ from _csv import Error, __version__, writer, reader, register_dialect, \ __doc__ from _csv import Dialect as _Dialect -try: - from cStringIO import StringIO -except ImportError: - from StringIO import StringIO +from io import StringIO __all__ = [ "QUOTE_MINIMAL", "QUOTE_ALL", "QUOTE_NONNUMERIC", "QUOTE_NONE", "Error", "Dialect", "__doc__", "excel", "excel_tab", @@ -24,7 +20,7 @@ __all__ = [ "QUOTE_MINIMAL", "QUOTE_ALL", "QUOTE_NONNUMERIC", "QUOTE_NONE", "unregister_dialect", "__version__", "DictReader", "DictWriter" ] class Dialect: - """Describe an Excel dialect. + """Describe a CSV dialect. This must be subclassed (see csv.excel). Valid attributes are: delimiter, quotechar, escapechar, doublequote, skipinitialspace, @@ -50,7 +46,7 @@ class Dialect: def _validate(self): try: _Dialect(self) - except TypeError, e: + except TypeError as e: # We do this for compatibility with py2.3 raise Error(str(e)) @@ -69,6 +65,16 @@ class excel_tab(excel): delimiter = '\t' register_dialect("excel-tab", excel_tab) +class unix_dialect(Dialect): + """Describe the usual properties of Unix-generated CSV files.""" + delimiter = ',' + quotechar = '"' + doublequote = True + skipinitialspace = False + lineterminator = '\n' + quoting = QUOTE_ALL +register_dialect("unix", unix_dialect) + class DictReader: def __init__(self, f, fieldnames=None, restkey=None, restval=None, @@ -87,7 +93,7 @@ class DictReader: def fieldnames(self): if self._fieldnames is None: try: - self._fieldnames = self.reader.next() + self._fieldnames = next(self.reader) except StopIteration: pass self.line_num = self.reader.line_num @@ -97,18 +103,18 @@ class DictReader: def fieldnames(self, value): self._fieldnames = value - def next(self): + def __next__(self): if self.line_num == 0: # Used only for its side effect. self.fieldnames - row = self.reader.next() + row = next(self.reader) self.line_num = self.reader.line_num # unlike the basic reader, we prefer not to return blanks, # because we will typically wind up with a dict full of None # values while row == []: - row = self.reader.next() + row = next(self.reader) d = dict(zip(self.fieldnames, row)) lf = len(self.fieldnames) lr = len(row) @@ -126,9 +132,8 @@ class DictWriter: self.fieldnames = fieldnames # list of keys for the dict self.restval = restval # for writing short dicts if extrasaction.lower() not in ("raise", "ignore"): - raise ValueError, \ - ("extrasaction (%s) must be 'raise' or 'ignore'" % - extrasaction) + raise ValueError("extrasaction (%s) must be 'raise' or 'ignore'" + % extrasaction) self.extrasaction = extrasaction self.writer = writer(f, dialect, *args, **kwds) @@ -140,8 +145,8 @@ class DictWriter: if self.extrasaction == "raise": wrong_fields = [k for k in rowdict if k not in self.fieldnames] if wrong_fields: - raise ValueError("dict contains fields not in fieldnames: " + - ", ".join(wrong_fields)) + raise ValueError("dict contains fields not in fieldnames: " + + ", ".join(wrong_fields)) return [rowdict.get(key, self.restval) for key in self.fieldnames] def writerow(self, rowdict): @@ -181,7 +186,7 @@ class Sniffer: delimiters) if not delimiter: - raise Error, "Could not determine delimiter" + raise Error("Could not determine delimiter") class dialect(Dialect): _name = "sniffed" @@ -245,12 +250,10 @@ class Sniffer: if m[n]: spaces += 1 - quotechar = reduce(lambda a, b, quotes = quotes: - (quotes[a] > quotes[b]) and a or b, quotes.keys()) + quotechar = max(quotes, key=quotes.get) if delims: - delim = reduce(lambda a, b, delims = delims: - (delims[a] > delims[b]) and a or b, delims.keys()) + delim = max(delims, key=delims.get) skipinitialspace = delims[delim] == spaces if delim == '\n': # most likely a file with a single column delim = '' @@ -293,7 +296,7 @@ class Sniffer: additional chunks as necessary. """ - data = filter(None, data.split('\n')) + data = list(filter(None, data.split('\n'))) ascii = [chr(c) for c in range(127)] # 7-bit ASCII @@ -316,19 +319,17 @@ class Sniffer: charFrequency[char] = metaFrequency for char in charFrequency.keys(): - items = charFrequency[char].items() + items = list(charFrequency[char].items()) if len(items) == 1 and items[0][0] == 0: continue # get the mode of the frequencies if len(items) > 1: - modes[char] = reduce(lambda a, b: a[1] > b[1] and a or b, - items) + modes[char] = max(items, key=lambda x: x[1]) # adjust the mode - subtract the sum of all # other frequencies items.remove(modes[char]) modes[char] = (modes[char][0], modes[char][1] - - reduce(lambda a, b: (0, a[1] + b[1]), - items)[1]) + - sum(item[1] for item in items)) else: modes[char] = items[0] @@ -348,7 +349,7 @@ class Sniffer: consistency -= 0.01 if len(delims) == 1: - delim = delims.keys()[0] + delim = list(delims.keys())[0] skipinitialspace = (data[0].count(delim) == data[0].count("%c " % delim)) return (delim, skipinitialspace) @@ -391,7 +392,7 @@ class Sniffer: rdr = reader(StringIO(sample), self.sniff(sample)) - header = rdr.next() # assume first row is header + header = next(rdr) # assume first row is header columns = len(header) columnTypes = {} @@ -407,9 +408,9 @@ class Sniffer: if len(row) != columns: continue # skip rows that have irregular number of columns - for col in columnTypes.keys(): + for col in list(columnTypes.keys()): - for thisType in [int, long, float, complex]: + for thisType in [int, float, complex]: try: thisType(row[col]) break @@ -419,10 +420,6 @@ class Sniffer: # fallback to length of string thisType = len(row[col]) - # treat longs as ints - if thisType == long: - thisType = int - if thisType != columnTypes[col]: if columnTypes[col] is None: # add new column type columnTypes[col] = thisType |