+3

# Python List Slice

Hey Can somebody help me please with this question!! What is the output of this code? sqs = [0, 1, 4, 9, 16, 25, 36, 49, 64, 81] print(sqs[7:5:-1] The Answer is: [49, 36] But why????? Thanks for your Answers!

11/5/2018 3:17:00 PM

Nils

+6

-1 = len(array)-1 So you start slicing from the end of the array. The first parameter(7) is included in the slice but the 2nd parameter isn't. So the slice ends at the 6th element.

+4

print(sqs[7:5:-1]) 7:5=means start from 7 index and end at 4 index 5 will be not included.here you are going 7 to 5 means backward and you need -1 step for backward index. that's why output is = 7:5:-1=[49,36]

+3

var[start:when to stop:how to iterate] sqs[7:5:-1] -start in element 7 (49) -stop if we reach element 5 or pass . - -1 means we add -1 for iterations. So : 7 6 stop See? this results printing 7 element and 6 element (49, 36)

+1

+1

Maninder Singh Thanks!

+1

can you help me?

+1

what seems to be the problem?

0

Thanks Anya! so -1 means that the list is read backwards!?

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Nils yes. It's like LambdaDriver said.

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No problem Nils