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nums_lst = [x for y in matrix for x in y]

Could anyone please help me understand what does the line x for y in matrix for x in y mean? matrix is of type list[[]]

What is x and what is y in the matrix? Thank you for your help.

Patrick Haugh
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Jin Huang
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1 Answers1

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This is called list comprehension. There’s plenty of tutorials but it’s basically flattening 3 or 4 lines of code into one. Put anyway instead of creating a list within a loop you use this special syntax. Here’s a good description of the technique enter link description here

You can also use dictionary comprehensions.

Once you get used to the syntax then comprehensions do result in nice clean code.

I suggest the following learning path. Try figure out a basic list comprehension first, for example take a list of integers and turn it into a list of squared integers. Then move onto the two dimensional element.

Sol7
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