From d2b5b316ab5af6382de12ca7d7c018dfd8ee6073 Mon Sep 17 00:00:00 2001 From: R David Murray Date: Mon, 24 Feb 2014 15:35:19 -0500 Subject: [PATCH] #20628: make it clear that DictReader/Writer *fieldnames* is a Sequence. Patch by Sean Rodman. --- Doc/library/csv.rst | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/Doc/library/csv.rst b/Doc/library/csv.rst index 66b2fb4e09..04fc0f28ca 100644 --- a/Doc/library/csv.rst +++ b/Doc/library/csv.rst @@ -167,7 +167,11 @@ The :mod:`csv` module defines the following classes: .. class:: DictReader(csvfile, fieldnames=None, restkey=None, restval=None, dialect='excel', *args, **kwds) Create an object which operates like a regular reader but maps the information - read into a dict whose keys are given by the optional *fieldnames* parameter. + read into a dict whose keys are given by the optional *fieldnames* + parameter. The *fieldnames* parameter is a :ref:`sequence + ` whose elements are associated with the + fields of the input data in order. These elements become the keys of the + resulting dictionary. If the *fieldnames* parameter is omitted, the values in the first row of the *csvfile* will be used as the fieldnames. If the row read has more fields than the fieldnames sequence, the remaining data is added as a sequence @@ -180,7 +184,9 @@ The :mod:`csv` module defines the following classes: .. class:: DictWriter(csvfile, fieldnames, restval='', extrasaction='raise', dialect='excel', *args, **kwds) Create an object which operates like a regular writer but maps dictionaries onto - output rows. The *fieldnames* parameter identifies the order in which values in + output rows. The *fieldnames* parameter is a :ref:`sequence + ` of keys that identify the order in + which values in the dictionary passed to the :meth:`writerow` method are written to the *csvfile*. The optional *restval* parameter specifies the value to be written if the dictionary is missing a key in *fieldnames*. If the dictionary passed to -- 2.50.1