Variable name same as lambda function parameter

pedro_galher 0
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I wrote some code for iteratively opening some images and I realised that I inadvertently used the same name for the img variable x and for the parameters in the lambda function that converts the greyscale image to a binary of 1 and 0:

for i, x in enumerate(list_images):
  
    image_path = os.path.join(parent_directory, x)
    img = Image.open(image_path).convert('L')
    img = np.array(img.point(lambda x: 1 if x > 127 else 0))

To my surprise, the code did not show any error and it worked normally. I double-checked the results symply changing the lamdba parameter name to other different than x.

My question is: Why is there no conflict between the variable names? Is it because the variable for the lambda function is defined within another scope (the one corresponding to the lambda)?

lambda function python
1 Answers

Simply put, scope. The scope of the x is with in the lambda function. With in the lambda function your inner x shadows your outer x. Hence it works. The scope of the x in lambda is restricted to the lambda function, and hence cannot be accessed outside, hence it never effects the x outside.

Hassan Jalil0
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