Commit df714b9f authored by R David Murray's avatar R David Murray

#20628: make it clear that DictReader/Writer *fieldnames* is a Sequence.

Patch by Sean Rodman.
parent 6b532349
......@@ -145,7 +145,10 @@ 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 :mod:`sequence <collections.abc>` 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
......@@ -158,7 +161,8 @@ 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 :mod:`sequence
<collections.abc>` 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
......
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