Understanding "help" command description syntax - explanation needed

Mark Lawrence breamoreboy at yahoo.co.uk
Wed Nov 5 13:04:01 CET 2014


On 05/11/2014 11:55, Jean-Michel Pichavant wrote:
> ---- Original Message -----
>> From: "Ivan Evstegneev" <webmailgroups at gmail.com>
>> To: python-list at python.org
>> Sent: Wednesday, 5 November, 2014 12:00:16 PM
>> Subject: Understanding "help" command description syntax - explanation needed
>> So here is the question itself:
>>
>> If I use the help command to check the “range” command I get this
>> info:
>>
>>
>>
>> range(stop) -> range object
>>
>> range(start, stop[, step]) -> range object
>
> With python 2.7, when I type help(range), I get
>
> """
> Help on built-in function range in module __builtin__:
>
> range(...)
>      range([start,] stop[, step]) -> list of integers
>
>      Return a list containing an arithmetic progression of integers.
>      range(i, j) returns [i, i+1, i+2, ..., j-1]; start (!) defaults to 0.
>      When step is given, it specifies the increment (or decrement).
>      For example, range(4) returns [0, 1, 2, 3].  The end point is omitted!
>      These are exactly the valid indices for a list of 4 elements.
> """
>
> range([start,] stop[, step]) tells you how to call the range function, there's a start, stop and step argument.
> The purpose of these arguments are given by the longer description.
>
> brackets [] means that the argument is optional.
>
> Though there's nothing wrong with googling the function for help, I'm doing it all the time.
> Actually, the python documentation is a better place to get help on a particular function, just make sure you hit the correct version, for either python 2 or 3:
>
> https://docs.python.org/2/library/functions.html#range
>
> I'm using python's help function only when working offline.
>
> JM
>

There is an issue on the bug tracker about the difference between help 
for range between Python 2 and 3, see http://bugs.python.org/issue22785

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence




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