Iteration index

[Paul Winkler]

Marek Augustyn wrote:
> 
> Hello!
> 
> 1. Do I have to use additional variable when I want to know iteration index?
> Example:
> 
> s = ('a', 'b', 'ala', 'a')
> i = 0 # additional variable
> for el in s:
>     print i, el
>     i += 1

Most people do use the extra variable, but I think it's safe to
say that 
most python programmers use the built-in range() and len()
functions, like so:

s = ('a', 'b', 'ala', 'a')
for i in range(len(s)):
    print i, s[i]


If len(s) is very large, you could use xrange() instead of
range().

I guess you could do it without the variable like this: 

!! WARNING -- this only works if you use a list instead of a tuple
AND you know that the list contains no duplicate items!!

s = ['a', 'b', 'ala', 'a']
for el in s:
    print s.index(el), el

But I wouldn't do that - too many assumptions about the input.
In the example given, it prints this:

0 a
1 b
2 ala
0 a

... not what you want.

> 
> 2. Are there block comments in Python? (like /* */ in C)

Nope, but you can use doc strings with triple quotes:

"""
This string can be very long
and contain as much stuff
as you want.
"""



HTH,

--PW