Python loop counter in a for loop

Question

In my example code below  is the counter   0 really required  or is there a better  more Python  way to get access to a loop counter  I saw a few PEPs related to loop counters  but they were either deferred or rejected  PEP 212 and PEP 281    This is a simplified example of my problem  In my real application this is done with graphics and the whole menu has to be repainted each frame  But this demonstrates it in a simple text way that is easy to reproduce   Maybe I should also add that I m using Python 2 5  although I m still interested if there is a way specific to 2 6 or higher     Draw all the options  but highlight the selected index def draw menu options  selected index       counter   0     for option in options          if counter    selected index              print        s    option         else              print        s    option         counter    1   options     Option 0    Option 1    Option 2    Option 3    draw menu option  2    Draw menu with  Option2  selected   When run  it outputs        Option 0      Option 1      Option 2      Option 3

User · Answer

I ll sometimes do this   def draw menu options  selected index       for i in range len options            if i    selected index              print        s    options i          else              print        s    options i    Though I tend to avoid this if it means I ll be saying options i  more than a couple of times

User · Answer

Use enumerate   like so   def draw menu options  selected index       for counter  option in enumerate options           if counter    selected index              print        s    option         else              print        s    option      options     Option 0    Option 1    Option 2    Option 3   draw menu options  2    Note  You can optionally put parenthesis around counter  option  like  counter  option   if you want  but they re extraneous and not normally included

User · Answer

enumerate is what you are looking for   You might also be interested in unpacking     The pattern x  y  z    1  2  3     also works in loops  l     28   M     4   a     1990   r    for x  y in l      print x     prints the numbers 28  4  1990    and also for index   x  y  in enumerate l       print x     prints the numbers 28  4  1990   Also  there is itertools count   so you could do something like  import itertools  for index  el in zip itertools count     28  4  1990        print el     prints the numbers 28  4  1990

User · Answer

You could also do    for option in options        if option    options selected index               print       else              print   Although you d run into issues if there are duplicate options

[loops] Python loop counter in a for loop

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