what num[~ Wavy lines ] in python means?

Question

I encountered a problem in leetcode named 246. Strobogrammatic Number

class Solution(object):
    def isStrobogrammatic(self, num):
        return all(num[i] + num[~i] in '696 00 11 88' for i in range(len(num)/2+1))

i am curious of what num[~i] means?

Duplicate of https://stackoverflow.com/questions/8305199/the-tilde-operator-in-python — hikerjobs, Mar 05 '18 at 03:54
Possible duplicate of [The tilde operator in Python](https://stackoverflow.com/questions/8305199/the-tilde-operator-in-python) — donkopotamus, Mar 05 '18 at 04:00

23k · Answer 1 · 2018-03-05T04:01:31.090

4

~ is the NOT Bitwise operator. Essentially it will invert all the bits.

So if you performed ~ on 4 bits like 0101, it would invert to 1010.

Here's a helpful answer that I found, as Bitwise operators can turn into a complex topic that has surely been covered on SO.

edited Mar 05 '18 at 04:01

answered Mar 05 '18 at 03:54

23k

score 1 · Answer 2 · edited Mar 05 '18 at 04:28

1

for i in range(10):
...  print(i, ~i)
...
0 -1
1 -2
2 -3
3 -4
4 -5
5 -6
6 -7
7 -8
8 -9
9 -10

It (probably) means reversing the binany representation of the number.

edited Mar 05 '18 at 04:28

user3483203

answered Mar 05 '18 at 03:52

mickeyandkaka

2 Answers2