csv¶

CSV parsing and writing.

This module provides classes that assist in the reading and writing of Comma Separated Value (CSV) files, and implements the interface described by PEP 305. Although many CSV files are simple to parse, the format is not formally defined by a stable specification and is subtle enough that parsing lines of a CSV file with something like line.split(”,”) is bound to fail. The module supports three basic APIs: reading, writing, and registration of dialects.

DIALECT REGISTRATION:

Readers and writers support a dialect argument, which is a convenient handle on a group of settings. When the dialect argument is a string, it identifies one of the dialects previously registered with the module. If it is a class or instance, the attributes of the argument are used as the settings for the reader or writer:

class excel:

delimiter = ‘,’ quotechar = ‘”’ escapechar = None doublequote = True skipinitialspace = False lineterminator = ‘rn’ quoting = QUOTE_MINIMAL

SETTINGS:

• quotechar - specifies a one-character string to use as the

  quoting character. It defaults to ‘”’.

• delimiter - specifies a one-character string to use as the

  field separator. It defaults to ‘,’.

• skipinitialspace - specifies how to interpret whitespace which

  immediately follows a delimiter. It defaults to False, which means that whitespace immediately following a delimiter is part of the following field.

• lineterminator - specifies the character sequence which should

  terminate rows.

• quoting - controls when quotes should be generated by the writer.

  It can take on any of the following module constants:

  csv.QUOTE_MINIMAL means only when required, for example, when a

  field contains either the quotechar or the delimiter

  csv.QUOTE_ALL means that quotes are always placed around fields. csv.QUOTE_NONNUMERIC means that quotes are always placed around

  fields which do not parse as integers or floating point numbers.

  csv.QUOTE_NONE means that quotes are never placed around fields.

• escapechar - specifies a one-character string used to escape

  the delimiter when quoting is set to QUOTE_NONE.

• doublequote - controls the handling of quotes inside fields. When

  True, two consecutive quotes are interpreted as one during read, and when writing, each quote character embedded in the data is written as two quotes