Python | Remove List elements containing given String character

Last Updated : 22 Apr, 2020

Sometimes, while working with Python lists, we can have problem in which we need to perform the task of removing all the elements of list which contain at least one character of String. This can have application in day-day programming. Lets discuss certain ways in which this task can be performed.

Method #1 : Using loop
This is brute force way in which this task can be performed. In this, we iterate for all list elements and check for occurrence of any character using loop.

# Python3 code to demonstrate working of 
# Remove List elements containing String character
# Using loop
  
# initializing list
test_list = ['567', '840', '649', '7342']
  
# initializing string 
test_str = '1237'
  
# printing original list
print("The original list is : " + str(test_list))
  
# Remove List elements containing String character
# Using loop
res = []
for sub in test_list:
    flag = 0
    for ele in sub:
        if ele in test_str:
            flag = 1
    if not flag:
        res.append(sub)
  
# printing result 
print("The list after removal : " + str(res)) 

Output :

The original list is : ['567', '840', '649', '7342']
The list after removal : ['840', '649']

Method #2 : Using list comprehension
This is another way to perform this task. This is similar to above method. In this we perform the task in similar way as above just as one liner.

# Python3 code to demonstrate working of 
# Remove List elements containing String character
# Using list comprehension
  
def check_pres(sub, test_str):
    for ele in sub:
        if ele in test_str:
            return 0
    return 1
      
# initializing list
test_list = ['567', '840', '649', '7342']
  
# initializing string 
test_str = '1237'
  
# printing original list
print("The original list is : " + str(test_list))
  
# Remove List elements containing String character
# Using list comprehension
res = [ele for ele in test_list if check_pres(ele, test_str)]
  
# printing result 
print("The list after removal : " + str(res)) 

Output :

The original list is : ['567', '840', '649', '7342']
The list after removal : ['840', '649']

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Python | Remove List elements containing given String character