Python large list error -

i did following program generate list of consecutive numbers. however, computations seem fail more 70.000 elements in list. tried using pycharm ide , python console. result same. i'm using python 3.4.1 32-bit version. should ? can cause ?

from pylab import *  = 100000                    # number of elements my_array my_array = [i in range(a)]  missing_number = randint(a) print('generate random number: ', missing_number) my_array.remove(missing_number)   # remove random generated number my_array print('the number of elements of list is: ', len(my_array))     #length of  my_array print('the sum of list :',sum(my_array))             # sum  sum02 = (a *(a-1)/2)        #  sum of consecutive numbers print('the complete sum of consecutive numbers:',int(sum02),'\n') print('and missing number is:', int(sum02) - sum(my_array)) 

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i reproduce result have locally on machine :

c:\util\python34\python.exe "find_missing_number_2.py"

generate random number:  15019 number of elements of list is:  99999 sum of list : 704967685 complete sum of consecutive numbers: 4999950000 , missing number is: 4294982315 process finished exit code 0  

it doesn't result error. it's doing wrong calculations can see if compare 2 variables: missing_number 1 resulted int(sum02)-sum(my_array)

from pylab import * from numpy import *. includes numpy.sum function explicitly says arithmetic modular when using integer types, , no error raised on overflow.

to avoid used builtin sum function, either shown reut sharabani, or not doing from pylab import *, bad practice anyway. can replace built-in functions, without noticing. far know, replaces @ least sum , @ moment, i'm not sure that's all, , can't sure won't replace others in future.