What Do Square Brackets in Function and Class Documentation Mean?

Parsing Square Brackets in Function and Class Documentation

When encountering square brackets ([ ]) in function or class documentation, it's crucial to understand that they symbolize optional arguments. In the case of csv.dictreader, as illustrated in its documentation:

class csv.DictReader(csvfile[, fieldnames=None[, restkey=None[, restval=None[, dialect='excel'[, *args, **kwds]]]]])

The square brackets indicate that all arguments within them are optional. Therefore, only the csvfile argument is required for class instantiation, while the rest (fieldnames, restkey, restval, and dialect) are optional and can be omitted.

For example, if you wish to specify only csvfile and dialect, you can do so using explicit keyword arguments, as seen below:

csv.DictReader(file('test.csv'), dialect='excel_tab')

For a more thorough understanding of keyword arguments, refer to section 4.7.2 of the Python tutorial at python.org.

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