How to parse an integer from a string in Zig?

Question

What is the proper way to parse an integer from a string in Zig, while being able to specify the resulting integer type?

const foo = "96";

How would I convert foo to an i32, for example?

solvin dev · Accepted Answer

std.fmt.parseInt (https://ziglang.org/documentation/master/std/#std.fmt.parseInt) from the standard library (https://ziglang.org/documentation/master/std/) is what you are looking for. It allows parsing integers of various types (u32, i64, u8, etc.), as well as bases (binary, hexadecimal, etc.).

Example:

const foo = "96";

const foo_integer = try std.fmt.parseInt(i32, foo, 10);

Inputting a value of 0 for the base allows parseInt to auto-detect the base for you based on prefixes.

- Prefix of 0b - Base 2 (Binary)
- Prefix of 0o - Base 8 (Octal)
- Prefix of 0x - Base 16 (Hexadecimal)

Another thing to note is that underscores (_) are safely ignored in the input string and will not throw a parse error.

You may also want to look at std.fmt.parseUnsigned (https://ziglang.org/documentation/master/std/#std.fmt.parseUnsigned) if you expect only unsigned integers, it functions very similarly.

How to parse an integer from a string in Zig?

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