Python | Concatenate two lists into a list of tuples

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Examples :

  Input:  list1 = [1, 2, 3] list2 = [’a’,’ b’, ’c ’]  Output:  [(1,’ a’), (2, ’b’), (3,’ c’)]  Input:  list1 = [1, 2, 3, 4] list2 = [1, 4, 9]  Output:  [(1, 1), (2, 4), (3, 9), (4, ’’)] 

Approach # 1: Naive
Concatenate both lists into a list of tuples using a for loop. But the downside is that the two lists must be the same length.

def merge (list1, list2) :

merged_list = [(list1 [i], list2 [i]) for i in range ( 0 , len (list1))]

return merged_list


# Driver code

l ist1 = [ 1 , 2 , 3 ]

list2 = [ ’a’ , ’ b’ , ’c’ ]

print (merge (list1, list2))

Exit:

 [(1, ’a’), (2,’ b’), (3, ’c’)] 

Approach # 2: Naive but more effective
This method fixes the above drawback and works well with unequal lengths of two lists. This also provides a try catch error for the Index error.

def merge (list1, list2):

merged_list = []

for i in range ( max (( len (list1), len (list2)))) :

while T rue :

try :

tup = (list1 [i], list2 [i])

except IndexError:

if len (list1) & gt; len (list2):

list2.append (’’)

tup = (list1 [i], list2 [i])

elif len (list1) & lt; len (list2):

list1.append (’’)

tup = (list1 [i], list2 [i])

continue

merged_list.append (tup)

break

return merged_list


# Driver code

list1 = [ 1 , 2 , 3 ]

list2 = [ ’a’ , ’ b’ , ’c’ ]

print (merge (list1, list2))

Exit:

 [(1, ’a’), (2,’ b’), (3, ’c’)] 

Approach # 3 Using zip ()
using the zip () method to concatenate two list items and then inject them into a tuple.

def merge (list1, list2):

merged_list = tuple ( zip (list1, list2))

return merged_list


# Driver code

list1 = [ 1 , 2 , 3 ]

list2 = [ ’a’ , ’ b’ , ’c’ ]

print (merge (list1, list2))

Exit:

 ((1, ’a’), (2, ’b’), (3,’ c’)) 

Approach # 4: Using enumerate (), an alternative to zip ().

This method uses two for loops to iterate through lists and concatenate the two lists.

def merge (list1 , list2):

merged_list = [(p1, p2) for idx1, p1 in enumerate (list1)

for idx2, p2 in enumerate (list2) if idx1 = = idx2]

return merged_list


# Driver code

list1 = [ 1 , 2 , 3 ]

list2 = [ ’a’ , ’ b’ , ’c’ ]

print (merge (list1, list2))

Exit:

 [(1, ’a’), (2,’ b’) , (3, ’c’)] 

Approach # 5 Using map () and lambda .

# Using map () and lambda

def listOfTuples (l1, l2):

return list ( map ( lambda x, y: (x, y), l1, l2))


Driver code

list1 = [ 1 , 2 , 3 ]

list2 = [ ’a’ , ’b’ , ’ c’ ]

print (listOfTuples (list1, list2))

Exit :

 [(1, ’a’), (2,’ b’), (3, ’c’)] 

👻 Read also: what is the best laptop for engineering students?

We hope this article has helped you to resolve the problem. Apart from Python | Concatenate two lists into a list of tuples, check other Loops-related topics.

Want to excel in Python? See our review of the best Python online courses 2022. If you are interested in Data Science, check also how to learn programming in R.

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Manuel Gonzalez

Prague | 2022-11-27

Maybe there are another answers? What Python | Concatenate two lists into a list of tuples exactly means?. Checked yesterday, it works!

Angelo Zelotti

Rome | 2022-11-27

Thanks for explaining! I was stuck with Python | Concatenate two lists into a list of tuples for some hours, finally got it done 🤗. I just hope that will not emerge anymore

Ken Ungerschaft

Prague | 2022-11-27

Simply put and clear. Thank you for sharing. Python | Concatenate two lists into a list of tuples and other issues with Python functions was always my weak point 😁. Will use it in my bachelor thesis

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