Multiple String Substitution

Replaces multiple substrings in a character vector simultaneously, avoiding the cascade problem where an earlier replacement becomes the target of a later one. Internally uses temporary unique tokens as an intermediate step.

Usage

mGsub(x, patterns, replacements)

Arguments

x

a character vector in which substitutions are performed.

patterns

a character vector of substrings to search for (fixed = TRUE).

replacements

a character vector of replacement strings, in the same order as patterns.

Value

a character vector of the same length as x.

Details

Patterns are processed in the given order. For overlapping patterns (e.g. "AB" and "A"), list the longer pattern first, otherwise the shorter one consumes its characters before the longer one is considered.

See also

mReplace() for exact whole-element replacement.

Other string.transform: char-ascii-conversion, strSplitToCol(), strSplitToDummy()

Examples

mGsub(c("foo bar", "bar foo"), c("foo", "bar"), c("bar", "foo"))
#> [1] "bar foo" "foo bar"
# [1] "bar foo" "foo bar"

# Without simultaneous replacement this would yield "foo foo"
# with sequential gsub().

x <- c("A", "B", "AB", "BA")
mGsub(x, patterns = c("A", "B"), replacements = c("BX", "CY"))
#> [1] "BX"   "CY"   "BXCY" "CYBX"