[Tutor] Problems with iterations and breaking loops.

[Emile van Sebille]

On 3/17/2010 8:02 AM Karjer Jdfjdf said...
> I'm having problems with iterations and loops. So I'm curious about the best Python-way to do iterations of lists (in if, while etc statements) and breaking of loops.
>
> I have a list of tuples with 2 values. I want to perform calculations on all of these for each value in a range of values (e.g. 100 to 110).
>
>
> list_of_tuples = [(90629, 4644), (90706, 4617), (90729, 4709)]
>
> #start value
> n = 100
> #maximum value
> nmax = 110
>
> #First I create a list for the values
> range_list = []
> while n<  int(nmax+1):
>      range_list.append(n)
>      n = n + 1
>
> print range_list
>

Look up the documentation for range -- there is an easier answer.

>
> for i in range_list:
>      for t in list_of_tuples:
>          val1 = t[0]
>          val2 = t[1]

you can also unpack a tuple like:

for val1,val2 in list_of_tuples:

>          print "do stuff with\t" + str(val1) + '\t' + str(val2) + \
>                '\tfor rangevalue\t' + str(i)
>
> But I think that the rangelist is not needed and it can be done better (and faster for large quantities of data). I think it's better to have somethng like the code below. But I'm having problems with breaking the second loop and returning to the first loop. If I put in another while-statement befor the for-statement it stops after 1 run and it has to continue until the end of the range.
>