replaceFirst

Common
JVM
JS
Native
1.0
fun replaceFirst(
    input: CharSequence,
    replacement: String
): String

(Common source) (JVM source) (JS source) (Native source)
For JVM

Replaces the first occurrence of this regular expression in the specified input string with specified replacement expression.

The replacement string may contain references to the captured groups during a match. Occurrences of ${name} or $index in the replacement string will be substituted with the subsequences corresponding to the captured groups with the specified name or index. In case of $index the first digit after '$' is always treated as part of group reference. Subsequent digits are incorporated into index only if they would form a valid group reference. Only the digits '0'..'9' are considered as potential components of the group reference. Note that indexes of captured groups start from 1, and the group with index 0 is the whole match. In case of ${name} the name can consist of latin letters 'a'..'z' and 'A'..'Z', or digits '0'..'9'. The first character must be a letter.

Backslash character '\' can be used to include the succeeding character as a literal in the replacement string, e.g, \$ or \\. Regex.escapeReplacement can be used if replacement have to be treated as a literal string.

Note that named capturing groups are supported in Java 7 or later.

Parameters

input - the char sequence to find a match of this regular expression in

replacement - the expression to replace the found match with

Exceptions

RuntimeException - if replacement expression is malformed, or capturing group with specified name or index does not exist

Return the result of replacing the first occurrence of this regular expression in input with the result of evaluating the replacement expression

For JS

Replaces the first occurrence of this regular expression in the specified input string with specified replacement expression.

The replacement string may contain references to the captured groups during a match. Occurrences of $index in the replacement string will be substituted with the subsequences corresponding to the captured groups with the specified index. The first digit after '$' is always treated as part of group reference. Subsequent digits are incorporated into index only if they would form a valid group reference. Only the digits '0'..'9' are considered as potential components of the group reference. Note that indexes of captured groups start from 1, and the group with index 0 is the whole match.

Backslash character '\' can be used to include the succeeding character as a literal in the replacement string, e.g, \$ or \\. Regex.escapeReplacement can be used if replacement have to be treated as a literal string.

Note that referring named capturing groups by name is not supported currently in Kotlin/JS. However, you can still refer them by index.

Parameters

input - the char sequence to find a match of this regular expression in

replacement - the expression to replace the found match with

Exceptions

RuntimeException - if replacement expression is malformed, or capturing group with specified name or index does not exist

Return the result of replacing the first occurrence of this regular expression in input with the result of evaluating the replacement expression

For Native

Replaces the first occurrence of this regular expression in the specified input string with specified replacement expression.

The replacement string may contain references to the captured groups during a match. Occurrences of $index in the replacement string will be substituted with the subsequences corresponding to the captured groups with the specified index. The first digit after '$' is always treated as part of group reference. Subsequent digits are incorporated into index only if they would form a valid group reference. Only the digits '0'..'9' are considered as potential components of the group reference. Note that indexes of captured groups start from 1, and the group with index 0 is the whole match.

Backslash character '\' can be used to include the succeeding character as a literal in the replacement string, e.g, \$ or \\. Regex.escapeReplacement can be used if replacement have to be treated as a literal string.

Note that named capturing groups are not supported in Kotlin/Native.

Parameters

input - the char sequence to find a match of this regular expression in

replacement - the expression to replace the found match with

Exceptions

RuntimeException - if replacement expression is malformed, or capturing group with specified name or index does not exist

Return the result of replacing the first occurrence of this regular expression in input with the result of evaluating the replacement expression