Why Do Lambdas Created in Loops Reference the Last Object?

Customizing Lambda Creation within Loops

When working with lists of objects and attempting to create lambdas inside a loop that access object attributes, you may encounter a problem where all lambdas reference the last object in the list.

To address this, the key is to capture the correct object reference for each lambda. The following code snippet provides an improved solution:

lambdas_list = []
for obj in obj_list:
    lambdas_list.append(lambda obj=obj: obj.some_var)

By setting obj=obj as a keyword argument in the lambda function, you create a new scope for obj within each iteration. This ensures that each lambda captures the correct object reference, isolating it from changes in subsequent loop iterations.

As a result, when you iterate over the lambdas_list and call each function, you will get the expected results for each object in the obj_list. This method effectively addresses the issue of all lambdas referencing the last object in the list and provides a more robust and pythonic solution.

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