An interesting beginner question: why we need colon at all in the python language?

Dave Angel davea at ieee.org
Mon Jul 11 16:36:48 CEST 2011


On 01/-10/-28163 02:59 PM, Anthony Kong wrote:
> Hi, all,
>
> Lately I am giving some presentations to my colleagues about the python
> language. A new internal project is coming up which will require the use of
> python.
>
> One of my colleague asked an interesting:
>
> *If Python use indentation to denote scope, why it still needs semi-colon at
> the end of function declaration and for/while/if loop?*
>
> My immediate response is: it allows us to fit statements into one line. e.g.
> if a == 1: print a
>
> However I do not find it to be a particularly strong argument. I think PEP8
> does not recommend this kind of coding style anyway, so one-liner should not
> be used in the first place!
>
> Is there any other reasons for use of semi-colon in python?
>
>
> Cheers
>
You're confusing the colon with the semi-colon.  If you want two 
statements on the same line, you use a semi-colon.

The character you're asking about is the colon.  It goes at the end of 
an if, else, for, with, while statement.  I doubt it's absolutely 
essential, but it helps readability, since a conditional expression 
might span multiple lines.
         if someexpression ==
               someotherexpression:
             body_of_the_conditional

DaveA




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