What does a pipe character in python slice notation do?

Question

In python slice notation for lists and tuples, I noticed that a pipe character doesn't throw an error. I'm not sure what exactly it does though, as the results seem a little random.

testA = [1,2,3,4,5,6,7,8,9]

Given that

testA[0:3]

gives

[1, 2, 3]

and

testA[4:6]

gives

[5, 6]

What does this pipe do?

testA[0:3|4:6]

it gives

[1, 7]

Any ideas?

@gspr I guess that begs the question, what does bitwise-or do with slices? — Peter Wood, Mar 25 '19 at 16:05
@gspr I don't think this is a duplicate. It was answered below, I could not have come to that conclusion from the answer offered as a duplicate. — Coffee and Code, Mar 27 '19 at 10:34

score 8 · Accepted Answer · answered Mar 25 '19 at 16:05

8

testA[0:3|4:6]

evaluates as

testA[0 : (3 | 4) : 6]

Which, in turn, evaluates via bitwise-or to

testA[0 : 7 : 6]

And this corresponds to the range 0 : 7 with a step size of 6. Hence only the first and last index are used.

answered Mar 25 '19 at 16:05

Konrad Rudolph

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What does a pipe character in python slice notation do?

Given that

gives

and

gives

What does this pipe do?

it gives

1 Answers1