Python – Length Conditional Concatenation

Given a list of strings, perform concatenation of Strings whose length is greater than K.

Input : test_list = [“Gfg”, ‘is’, “Best”, ‘for’, ‘CS’, ‘Everything’], K = 3
Output : BestEverything 
Explanation : All elements with Length > 3 are concatenated. 

Input : test_list = [“Gfg”, ‘is’, “Best”, ‘for’, ‘CS’, ‘Everything’], K = 1 
Output : GfgisBestforCSEverything 
Explanation : All elements with Length > 1 are concatenated.

Method #1: Using loop + len():
This offers a brute way to solve this problem. In this, we iterate for each string and perform concatenation if the string length is greater than K using len().

Python3

# Python3 code to demonstrate working of
# Length Conditional Concatenation
# Using loop + len()

# initializing lists
test_list = ["Gfg", 'is', "Best", 'for', 'CS', 'Everything']

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

# initializing K
K = 2

# loop to run through all the elements
res = ''
for ele in test_list:

    # using len() to check for length
    if len(ele) > 2:
        res += ele

# printing result
print("String after Concatenation : " + str(res))

Output

The original list : ['Gfg', 'is', 'Best', 'for', 'CS', 'Everything']
String after Concatenation : GfgBestforEverything

Method #2 : Using join() + filter() + lambda + len():
The combination of above functions can be used to solve this problem. In this, we perform concatenation using join(), filter and lambda are used for conditional check using len().

Python3

# Python3 code to demonstrate working of
# Length Conditional Concatenation
# Using join() + filter() + lambda + len()

# initializing lists
test_list = ["Gfg", 'is', "Best", 'for', 'CS', 'Everything']

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

# initializing K
K = 2

# join() performing Concatenation of required strings
res = ''.join(filter(lambda ele: len(ele) > K, test_list))

# printing result
print("String after Concatenation : " + str(res))

Output

The original list : ['Gfg', 'is', 'Best', 'for', 'CS', 'Everything']
String after Concatenation : GfgBestforEverything

Method#3: Using list comprehension + join():
This method lists strings whose length is greater than the defined number. With the help of join method, we can join the list in string. 

Python3

# Python3 code to demonstrate working of
# Length Conditional Concatenation
# Using list comprehension + join

# Initializing lists
test_list = ["Gfg", 'is', "Best", 'for', 'CS', 'Everything']

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

# Initializing K
K = 3

# list comprehension make list of string with greater length
# join() performing Concatenation of required strings
temp = [x for x in test_list if len(x) > K]
res = "".join(temp)

# Printing result
print("String after Concatenation : " + str(res))

Output

The original list : ['Gfg', 'is', 'Best', 'for', 'CS', 'Everything']
String after Concatenation : BestEverything