Evaluating expression :- Javascript vs Python

Question

The following expression results different result in Javascript in Python and Javascript:-

Python:-

a, b, c, e, f, h = 271733878, 4023233417, 5858469028, -389564586, 2562383102, 1634886000

a = a + (c & b | ~c & f) + h + e  # 4965557782

Javascript:-

a = 271733878;
b = 4023233417;
c = 5858469028;
e = -389564586
f = 2562383102;
h = 1634886000;

a = a + (c & b | ~c & f) + h + e; // 670590486

console.log(a)

How is the evaluation of the same expression differ in 2 languages?

Even evaluating the mathematical expressions? that sounds weird!! Should be something more. — Praful Bagai, Mar 04 '19 at 10:11
Bitwise calculations always depend on the bit representation of the value, and are thereby very specific to the language/platform used. There isn't really any one "right" answer. — deceze, Mar 04 '19 at 10:14
Found the solution. Converting the python number to 32-bit works. — Praful Bagai, Mar 04 '19 at 10:17

score 2 · Answer 1 · answered Mar 04 '19 at 10:08

2

~c is evaluated differently in Python and Javascript.

~c is the negation of the c value. This is done by inverting the bits of the value. As such, the value differs in different languages because they probably use a different amount of bits to store int values, which will result in a different ~value.

Javascript:

~c = -1563501733

Python:

~c = -5858469029

answered Mar 04 '19 at 10:08

H. Figueiredo

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Any solution to this, for me to make it behave similarly? – Praful Bagai Mar 04 '19 at 10:10
Converting the python number to 32-bit works. – Praful Bagai Mar 04 '19 at 10:19
Yep, that was what I was about to suggest! Glad you found your answer – H. Figueiredo Mar 04 '19 at 10:27

Evaluating expression :- Javascript vs Python

1 Answers1