Convert Strings to Integers/Floats in Python

Strings to integer

To convert a string to an integer:

>>> x = '1234'
>>> int(x)
1234

Strings to float

To convert a string to float:

>>> x = '1234'
>>> float(x)
1234.0

>>> y = '1234.678'
>>> float(y)
1234.6780000000001

but, convertion of ’1234.678′ to integer using int() will gives an error.

>>> int(y)
Traceback (most recent call last):
File "<pyshell#4>", line 1, in <module>
int(y)
ValueError: invalid literal for int() with base 10: '1234.678'

A workaround is by first converting to float, then to integer:

>>> y = '1234.678'
>>> int(float(y))
1234

List/tuple of strings to list of integers

1. Using list comprehension

   >>> x = ['07', '11', '13', '14', '28']
   >>> [int(i) for i in x]
   [7, 11, 13, 14, 28]

2. Using map

   >>> x = ['07', '11', '13', '14', '28']
   >>> list(map(int, x))
   [7, 11, 13, 14, 28]

   Mix of integers and floats

   >>> x = ['7.424124', '11', '13.423', '14.53453656', '28.2']
   >>> list(map(int, map(float, x)))
   [7, 11, 13, 14, 28]

List/tuple of strings to list of floats

1. Using list comprehension

   >>> x = ['7.424124', '1', '13.423', '14.53453656', '28.2']
   >>> [float(i) for i in x]
   [7.4241239999999999, 1.0, 13.423, 14.534536559999999, 28.199999999999999]
   

2. Using map

   >>> x = ['7.424124', '1', '13.423', '14.53453656', '28.2']
   >>> list(map(float, x))
   [7.4241239999999999, 1.0, 13.423, 14.534536559999999, 28.199999999999999]