replace and split with regex
Learn to do string operations with regex using replace and split.
replace with a regex
.replace() swaps the first match in a string for new text. Pair it with a regex and you gain the full power of patterns. The g flag replaces every match.
"2024-01-15".replace(/-/g, ".");
// "2024.01.15"This turns chores like "change every dash into a dot" into one line. You can also reuse the matched parts with $1, $2 references.
split with a regex
.split() breaks a string into pieces. Pass a regex as the separator and you can split on several delimiters at once.
"apple, banana; cherry".split(/[\s,]+/);
// ["apple", "banana", "cherry"]Here [\s,]+ means one or more spaces or commas. This turns messy text with mixed delimiters into a clean array in one pattern.
Exercise Turn spaces into dashes
Assign the result of text.replace() to cleanedText, turning every run of whitespace into a single dash. Use \s+ for the whitespace pattern and the global flag. Log the result with console.log.
Show example solution
replace takes a regex and a string. Use \s+ for a run of whitespace and the g flag for all.
Example solution:
let cleanedText = text.replace(/\s+/g, "-");
console.log(cleanedText);Test yourself
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What does the g flag do inside .replace()?
- replaces only the first match
- replaces nothing
- replaces every match
- replaces only the last match
Show answer
replaces every match — Correct! The g flag replaces every match.
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Call the replace method
const text = "2024-01-15"; const nice = text.____(/-/g, "."); console.log(nice);Show answer
const text = "2024-01-15"; const nice = text.replace(/-/g, "."); console.log(nice); -
Match methods with their behavior
- replace(re, s)
- replace
- split(re)
- split
- /g flag
- replace all
- $1, $2
- group reference