Getting wrong length for a list in if condition in python

Question

I have python list fin_list as follows:

fin_list = [
    ['1', '15'],
    ['3', '5', '1'],
    ['140', '147', '141'],
    ['133', '137', '134'],
    ['10', '12', '11'],
    ['12', '16', '15'],
    ['9', '10', '112576569'],
    ['8', '9', '10'],
    ['7', '8'],
    ['15', '16', '9', '133889916'],
    ['1', '3', '74228172'],
    ['3', '5', '1'],
    ['5', '6'],
]

and I want to remove all the lists having large numbers like 112576569, 133889916 and 74228172. Hence I am putting a condition in my code as:

if(all(i<=1000 for i in fin_list)):
    print fin_list

However when I put this condition , I get no output but when I put the condition, i>=1000, all the lists show up in the output.

score 3 · Accepted Answer · answered Oct 23 '16 at 14:17

You don't have numbers. You have strings. Strings are ordered lexicographically, and actual numbers (like 1000) are always ordered before other types when using comparisons in Python 2.

So '133889916' <= 1000 is always going to be false, because numbers are sorted before strings:

>>> '133889916' <= 1000
False
>>> '1000' <= 1000
False

Convert your strings to integers first:

if all(int(i) <= 1000 for i in fin_list):

Getting wrong length for a list in if condition in python

1 Answers1