parse-base — read a number in any radix

Parse a string of digits in a given base into an Int — the inverse of .base.

.parse-base(radix) reads a string written in that radix and returns the Int it denotes. It's the inverse of .base, which renders an integer into a radix.

Parsing from a base #

say "ff".parse-base(16);
say "101".parse-base(2);

255
5

"ff" in base 16 is 255; "101" in base 2 is 5.

Round-trip with .base #

.base renders an Int into a radix string; .parse-base reads it back — the two are exact inverses.

say 255.base(16);
say "FF".parse-base(16);
say 42.base(2).parse-base(2);

FF
255
42

Rendering 42 to binary and parsing it back returns 42 unchanged.

Notes #

• .base and .parse-base round-trip: 255.base(16) is "FF" and "FF".parse-base(16) is 255.
• The radix can be 2–36; digits above 9 use the letters a–z (case-insensitive).
• For base-16/8/2 literals in source code, the 0x/0o/0b prefixes or the :16<…> form are more direct — see Integer literals; parse-base is for radix strings computed or read at runtime.