Python | Extracting numbers from a list of strings



Method # 1: Using comprehension list + split()

This particular problem can be solved using the list comprehension function to expand the logic for all elements, and the split function does the task of splitting and extracting the target desired element.

# Python3 demo code
# Extract numbers from a list of strings
# using a list comprehension + split ()

 
# initializing list

test_list = [ `Rs. 24` , `Rs. 18` , `Rs. 8` , `Rs. 21` ]

 
# print original list

print ( "The original list:" + str (test_list))

 
# using list comprehension + split ()
# Extract numbers from a list of strings

res = [ int (sub.split ( ` .` ) [ 1 ]) for sub in test_list]

 
# print result

print ( "The list after Extracting numbers:" + str (res))

Output:

 The original list: [`Rs. 24`, `Rs. 18`, `Rs. 8`, `Rs. 21`] The list after Extracting numbers: [24, 18, 8, 21] 

Method # 2: Using join () + isnumeric () + list comprehension + map()

This method is preferred in cases where it is not predetermined that the numbers will be ordered in a certain way, i.e. this the method gives the flexibility to get a number from any possible position.

# Python3 demo code
# Extracting numbers from a list of strings
# using join () + isnumeric () + list comprehension + map ()

 
# initializing list

test_list = [ `Rs. 24` , `Rs. 18` , `Rs. 8` , `Rs. 21` ]

 
# print original list

print ( "The original list:" + str (test_list))

 
# using join () + isnumeric () + list comprehension + map ()
# Extract numbers from a list of strings

res = list ( map ( lambda sub: int (`` .join (

[ele for ele in sub if ele.isnumeric ()])), test_list))

 
# print result

print ( "The list after Extracting numbers:" + str (res))

Output:

 The original list: [`Rs. 24`, `Rs. 18`, `Rs. 8`, `Rs. 21`] The list after Extracting numbers: [24, 18, 8, 21]