Python standard library: csv

The csv module allows to read and write CSV files.

A script to read a csv file line by line:

import csv csv_file = open('data.csv', 'r') csv_reader = csv.reader(csv_file) header = next(csv_reader) for record in csv_reader: print('Record:') i = 0 for rec_value in record: print(' ' + header[i] + ': ' + rec_value) i += 1

The read csv file could be:

col 1,col 2,col 3 foo,bar,baz one,two,three 42,,0

Methods and properties

import csv
for e in sorted(dir(csv), key=lambda s: s.lower()): print(e)

`__all__`
`__builtins__`
`__cached__`
`__doc__`
`__file__`
`__loader__`
`__name__`
`__package__`
`__spec__`
`__version__`
`_Dialect`
`Dialect`	A class that specifies how different aspects of CSV files, such as double quotes, white spaces, delimiters etc.
`DictReader`	Returns an object similar to that returned by `reader`, but the CSV data can be accessed using a dict, i. e. with the names of the CSV columns.
`DictWriter`
`Error`
`excel`
`excel_tab`
`field_size_limit`
`get_dialect`
`list_dialects`
`QUOTE_ALL`
`QUOTE_MINIMAL`
`QUOTE_NONE`
`QUOTE_NONNUMERIC`
`re`
`reader`	Returns an object which will iterate over the lines produced by any object that supports the iterator protocol (such as file or list objects). Compare with `writer`.
`register_dialect`
`Sniffer`
`StringIO`	Compare with `io.StringIO`
`unix_dialect`
`unregister_dialect`
`writer`	Creates an object that converts data into delimited strings and sends them to any object that has a `write()` method.

Read tab separated values

Sometimes, the fields are not separated by commas but rather by tabulators. This can be indicated with the delimiter argument:

import csv

csv_file   = open('data.tsv', 'r')
csv_reader = csv.reader(csv_file, delimiter="\t")

header = next(csv_reader)

for record in csv_reader:

    print('Record:')

    i = 0
    for rec_value in record:
        print('  ' + header[i] + ': ' + rec_value)
        i += 1

Github repository about-python, path: /standard-library/csv/read_tab_seperated_values.py

the file being read might look like

col 1	col 2	col 3
foo	bar	baz
one	two	three
42		0

Github repository about-python, path: /standard-library/csv/data.tsv

Python standard library: csv

Methods and properties

Read tab separated values

See also