python - if A else 0 ? what does it mean? [duplicate]

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• Does Python have a ternary conditional operator? 19 answers

Hi I am recently studying a book that describes the data science from scratch. Then I found something like this :

A = [[1,2,3],[4,5,6]]

def shape(A) : 
  num_rows = len(A)
  num_cols = len(A[0]) if A else 0
  return num_rows, num_cols

I do not understand the part 'if A else 0'. I used to think that the if statement contains condition.. Could that possibly mean 'if the elements of A exist then return len(A[0]), else then return 0'? I am not quite sure. Please help. Thanks in advance :)