ValueError: invalid literal for int() with base 10: ''

Question

I am creating a program that reads a file and if the first line of the file is not blank, it reads the next four lines. Calculations are performed on those lines and then t

Answer 1

The following are totally acceptable in python:

• passing a string representation of an integer into int
• passing a string representation of a float into float
• passing a string representation of an integer into float
• passing a float into int
• passing an integer into float

But you get a ValueError if you pass a string representation of a float into int, or a string representation of anything but an integer (including empty string). If you do want to pass a string representation of a float to an int, as @katyhuff points out above, you can convert to a float first, then to an integer:

>>> int('5')
5
>>> float('5.0')
5.0
>>> float('5')
5.0
>>> int(5.0)
5
>>> float(5)
5.0
>>> int('5.0')
Traceback (most recent call last):
  File "", line 1, in 
ValueError: invalid literal for int() with base 10: '5.0'
>>> int(float('5.0'))
5