First for loop stops after first iteration

[buran]

30X20 would be 600 elements and you have 3200 (160x20). When you are reshaping, the total number of elements can’t be altered. That is why it works with break - f1 has 30 sub-lists and with brake it takes first element of each so you get 30x20 array to reshape

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with the simplified example would you share what desired output would be and how it is achieved