CODEWITHSUNDEEP
python
Careugh
Careugh

Reputation: 33

How to select even and odd intergers and get their totals

Ok im starting fresh and im going to bear everything I have exactly as it is.

NumbersMake.py

#This program writes 1 line of 12 random integers, each in the
#range from 1-100 to a text file.

def main():

    import random

    #Open a file named numbers.txt.
    outfile = open('numbers.txt', 'w')

    #Produce the numbers
    for count in range(12):
        #Get a random number.
        num = random.randint(1, 100)

        #Write 12 random intergers in the range of 1-100 on one line
        #to the file.
        outfile.write(str(num) + " ")

    #Close the file.
    outfile.close()
    print('Data written to numbers.txt')

#Call the main function
main()

The code above produces a text file that says:

60 90 75 94 54 12 10 45 60 92 47 65

The numbers above are 12 randomly generated integers sepearted by a space.

Would it be easier in the second script if I removed the spaces?

NumbersRead.py

#This program reads 12 random integers, outputs each number
#to its own line and then outputs the total of the even and odd  intergers.

def main():

    #Open a file named numbers.txt.
    infile = open('numbers.txt', 'r')

    #Read/process the file's contents.
    file_contents = infile.readline()
    numbers = file_contents.split(" ")
    odd = 0
    even = 0
    num = int(file_contents)
    for file_contents in numbers:
        if num%2 == 0:
            even += num
        else:
            odd += num

    #Close the file.
    infile.close()

    #Print out integer totals
    print('The total of the even intergers is: ', even)
    print('The total of the odd intergers is: ', odd)

#Call the main function
main()

The error I am receiving from the above script trying to process the total of the even and odd numbers is : 

Traceback (most recent call last):
  File "numbersread.py", line 29, in <module>
    main()
  File "numbersread.py", line 14, in main
    num = int(file_contents)
ValueError: invalid literal for int() with base 10: '60 90 75 94 54 12 10 45 60 92 47 65 '

I dont know what I am doing wrong.

Upvotes: 1

Views: 515

Answers (2)

Padraic Cunningham
Padraic Cunningham

Reputation: 180481

Presuming you have a list like ["1","2","3"...]

odd = sum(int(x) for x in  numbers if x % 2)
even = sum(int(x) for x in  numbers if not x % 2)

The best way is to use with to open your files and map to int first:

with open('numbers.txt') as f: # closes you files automatically
    numbers = map(int,f.read().split())


    odd = sum(x for x in numbers if x % 2) 
    even = sum(x for x in numbers if not x % 2)

If you had a very large file you would iterate over each line and sum as you go.

Also you only read a single line using readline, if you want only the first line replace f.read().split() with f.readline().split()

sum(x for x in numbers if x % 2) is a generator expression, Variables used in the generator expression are evaluated lazily when the next() method is called for generator object

Upvotes: 2

Joshua Snider
Joshua Snider

Reputation: 797

This looks suspiciously like homework to me, but here's what I'd put in place of your while loop

for num_str in numbers:
  num = int(num_str)
  if num%2 == 0: #Even
    even += num
  else:
    odd += num

Upvotes: 0

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