How to Change Tuple Values in Python?

Problem Formulation and Solution Overview

This article will show you how to change tuple values in Python.

To make it more interesting, we have the following running scenario:

Eddie, the Meteorologist at NTCV, has calculated an incorrect five (5) Day weather forecast. These values are saved as a Tuple and require updating.

💬 Question: How would we write code to change these Tuple values?

We can accomplish this task by one of the following options:

• Method 1: Use slicing
• Method 2: Use unpack and slicing
• Method 3: Use List and list comprehension
• Method 4: Use map() and a lambda

Method 1: Use Slicing

This example uses slicing in combination with the addition operator + to update an existing tuple element and insert an additional element.

nums_5day = (11, 12, 13, 14, 15)
nums_6day = nums_5day[:2] + (18, 21) + nums_5day[3:]
print(nums_6day)

The above code declares a Tuple containing projected temperatures for the next five (5) days. The results save to nums_5day.

The following line updates this Tuple by replacing an element and inserting an additional element using slicing. Thus making it projected temperatures for the next six (6) days. The results save to nums_6day and are output to the terminal.

Method 2: Use Unpack and Slicing

This example uses the unpack operator (*) and slicing to replace one (1) value from an existing tuple.

nums_5day = (11, 12, 13, 14, 15)
new_5day = (30, *nums_5day[1:])
print(new_5day)

The above code declares a Tuple containing projected temperatures for the next five (5) days. The results save to nums_5day.

The following line replaces the current temperature of 11 to 30. Then, the unpack (*) operator and slicing are used to keep the remaining elements. The results save to new_5day and are output to the terminal.

Method 3: Use List and List Comprehension

This example uses list and list comprehension to replace one (1) tuple value.

nums_5day = list((11, 12, 13, 14, 15))
new_5day = tuple([x + 5 if x == 13 else x for x in nums_5day])
print(new_5day)

The above code declares a Tuple containing projected temperatures for the next five (5) days. This is converted to a list and saved to nums_5day.

The following line uses list comprehension to replace the list element with the value of 13 to 18 (x+5). The results are converted to a Tuple, saved to new_5day and output to the terminal.

Method 4: Use map() and a lambda

This example uses the map() function and a lambda to replace three (3) tuple values.

nums_5day = list((11, 12, 13, 14, 15))
new_5day = tuple(map(lambda x: x+3 if x >= 12 and x <= 14 else x, nums_5day))
print(new_5day)

The above code declares a Tuple containing projected temperatures for the next five (5) days. This is converted to a list and saved to nums_5day.

The following line calls the map() function and passes it one (1) argument, a lambda. This result returns a map object. If this object was output to the terminal, an object reference similar to below would display.

This object is then converted from the map object to a Tuple and output to the terminal.

Summary

This article has provided four (4) ways to change Tuple values to select the best fit for your coding requirements.

Good Luck & Happy Coding!

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