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'''`csv`''' is a module that supports (de-)serializing CSV files. |
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| === Quote_All === Passing the constant `csv.QUOTE_ALL` as the `quoting` option on a CSV writer instructs the formatter to quote all fields using the `quotechar` option's character. ---- === Quote_Minimal === Passing the constant `csv.QUOTE_MINIMAL` as the `quoting` option on a CSV writer instructs the formatter to quote fields which contain ''special characters'' using the `quotechar` option's character. ''Special characters'' include all characters set in the `delimiter`, `quotechar`, and `lineterminator` options. ---- === Quote_NonNumeric === Passing the constant `csv.QUOTE_NONNUMERIC` as the `quoting` option on a CSV writer instructs the formatter to quote all non-numeric fields using the `quotechar` option's character. Passing as the `quoting` option on a CSV reader instructs the parser to convert all fields not quoted by the `quotechar` option's character into `float`s. ---- === Quote_None === Passing the constant `csv.QUOTE_NONE` as the `quoting` option on a CSV writer instructs the formatter to never quote fields. If the `delimiter` options's character is encountered in output, it is escaped with the `escapechar` options's character. If the `escapechar` option is not set when it is required, `csv.Error` is raised. Passing as the `quoting` option on a CSV reader instructs the parser to retain the `quotechar` option's character in data. ---- |
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| == Constants == The above functions take one of the following constants as a '''`quoting`''' option. The ensuing behavior often depends on other options passed on those functions, such as '''`quotechar`'''. ||'''Constant''' ||'''Meaning''' || ||`csv.QUOTE_ALL` ||quote all fields using the `quotechar` || ||`csv.QUOTE_MINIMAL` ||quote fields which contain special characters (`delimiter`, `quotechar`, and `lineterminator`) using the `quotechar` || ||`csv.QUOTE_NONNUMERIC`||quote all non-numeric fields using the `quotechar` || ||`csv.QUOTE_NONE` ||never quote fields; if `delimiter` is encountered in output, it is escaped with `escapechar` or `csv.Error` is raised|| If `csv.QUOTE_NONNUMERIC` is passed to a reader, all unquoted fields are cast to [[Python/Builtins/Types#Float|float]]. If `csv.QUOTE_NONE` is passed to a reader, all quotes are retained as part of a field's data. ---- |
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[[https://pymotw.com/3/csv/|Python Module of the Day article for csv]] |
Python Csv
csv is a module that supports (de-)serializing CSV files.
Contents
Usage
DictReader
DictWriter
Reader
import csv
with open(file, 'r', newline='', encoding='latin-1') as f:
r = csv.reader(f)
for row in r:
print(list(row))
Writer
import csv
data = [["John", "Doe", 123], ["Jane", "Doe", 456]]
with open(file, 'w', newline='', encoding='latin-1') as f:
w = csv.writer(f)
w.writerows(data)Alternatively, write individual rows.
for row in data:
w.writerow(data)
Constants
The above functions take one of the following constants as a quoting option. The ensuing behavior often depends on other options passed on those functions, such as quotechar.
Constant |
Meaning |
csv.QUOTE_ALL |
quote all fields using the quotechar |
csv.QUOTE_MINIMAL |
quote fields which contain special characters (delimiter, quotechar, and lineterminator) using the quotechar |
csv.QUOTE_NONNUMERIC |
quote all non-numeric fields using the quotechar |
csv.QUOTE_NONE |
never quote fields; if delimiter is encountered in output, it is escaped with escapechar or csv.Error is raised |
If csv.QUOTE_NONNUMERIC is passed to a reader, all unquoted fields are cast to float.
If csv.QUOTE_NONE is passed to a reader, all quotes are retained as part of a field's data.
See also
Python csv module documentation
Python Module of the Day article for csv