Split and Replace

Splitting by a simple and a multi-character separator; replacing and removing substrings.

// Feature: Splitting and replacing

// Syntax: `s.split(sep)` -> [str], `s.replace(old, new)` -> str

// When to use: simple CSV parsing, sanitization, transformations.


use std::csv
use std::log

// -- split: divides the string by a separator -------------------

let csv = "alice,bob,carol"
let names = csv.split(",")
print(names.len())  // 3

print(names[0])  // alice

print(names[1])  // bob

print(names[2])  // carol


// Iterate parts.

for n in csv.split(",") {
  print("- {n}")
}

// expected:

// - alice

// - bob

// - carol


// Separator longer than 1 character.

let log = "INFO::ready::server::up"
let pieces = log.split("::")
print(pieces.len())  // 4

print(pieces[0])  // INFO


// Empty string between delimiters becomes an empty piece.

let chunk = "a,,c"
print(chunk.split(",").len())  // 3


// -- replace: substitutes all occurrences ----------------------

let s = "hello world"
print(s.replace("o", "0"))  // hell0 w0rld

print(s.replace("world", "Zolo"))  // hello Zolo


// Original is unchanged.

print(s)  // hello world


// Chain: normalize spacing.

let raw = "a   b   c"
let clean = raw.replace("   ", " ")
print(clean)

// expected: a b c


// Replace a character with nothing — equivalent to removing.

print("a-b-c".replace("-", ""))
// expected: abc