Rust for Python Developers - Unsigned, Signed Integers and Casting

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Bitwise Negation

Rust uses ! for the Bitwise Negation (Bitwise NOT). This produces different results depends on the type.

As you see !2 with the unsigned type returns 4294967293 and with the signed type returns -3.

The bitwise negation on a signed integer returns the two’s complement as we saw previously in Rust signed two’s complement integer types.

Adding a Negative Number

The subtraction is the same as adding a negative number.

5 - 2 = 5 + (-2) = 3

This applies to binary as well.

0101 - 0010 
= 0101 + (-0010) // (1)
= 0101 + 1110    // (2)
= 0011           // this is 3 in decimal number.

We find -0010 by finding the two’s complement of 0010 that is 1110.