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 code Python module-related topics.

Want to excel in Python? See our review of the best Python online courses 2023. If you are interested in Data Science, check also how to learn programming in R.

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Manuel Lehnman

Texas | 2023-03-29

I was preparing for my coding interview, thanks for clarifying this - Python | Concatenate two lists into a list of tuples in Python is not the simplest one. Will get back tomorrow with feedback

Manuel Schteiner

Berlin | 2023-03-29

Simply put and clear. Thank you for sharing. Python | Concatenate two lists into a list of tuples and other issues with code Python module was always my weak point 😁. I am just not quite sure it is the best method

Boris Gonzalez

Massachussetts | 2023-03-29

I was preparing for my coding interview, thanks for clarifying this - Python | Concatenate two lists into a list of tuples in Python is not the simplest one. Checked yesterday, it works!

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