# Python | Concatenate two lists into a list of tuples

| | | | | | |

👻 Check our latest review to choose the best laptop for Machine Learning engineers and Deep learning tasks!

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.

By the way, this material is also available in other languages:

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!

## Shop

Learn programming in R: courses

\$FREE

Best Python online courses for 2022

\$FREE

Best laptop for Fortnite

\$399+

Best laptop for Excel

\$

Best laptop for Solidworks

\$399+

Best laptop for Roblox

\$399+

Best computer for crypto mining

\$499+

Best laptop for Sims 4

\$

Latest questions

PythonStackOverflow

Common xlabel/ylabel for matplotlib subplots

PythonStackOverflow

Check if one list is a subset of another in Python

PythonStackOverflow

How to specify multiple return types using type-hints

PythonStackOverflow

Printing words vertically in Python

PythonStackOverflow

Python Extract words from a given string

PythonStackOverflow

Why do I get "Pickle - EOFError: Ran out of input" reading an empty file?

PythonStackOverflow

Python os.path.join () method

PythonStackOverflow

Flake8: Ignore specific warning for entire file

## Wiki

Python | How to copy data from one Excel sheet to another

Common xlabel/ylabel for matplotlib subplots

Check if one list is a subset of another in Python

How to specify multiple return types using type-hints

Printing words vertically in Python

Python Extract words from a given string

Cyclic redundancy check in Python

Finding mean, median, mode in Python without libraries