like: Vectorised Pattern Matching with Keyboard Shortcut

In certe-medical-epidemiology/certetoolbox: A Certe R Package for Miscellaneous Functions

Vectorised Pattern Matching with Keyboard Shortcut

Description

Convenient wrapper around grepl() to match a pattern: x %like% pattern. It always returns a logical vector and is always case-insensitive (use x %like_case% pattern for case-sensitive matching). Also, pattern can be as long as x to compare items of each index in both vectors, or they both can have the same length to iterate over all cases.

Usage

like(x, pattern, ignore.case = TRUE)

x %like% pattern

x %unlike% pattern

x %like_case% pattern

x %unlike_case% pattern

Arguments

x	a character vector where matches are sought, or an object which can be coerced by as.character() to a character vector.
pattern	a character vector containing regular expressions (or a character string for fixed = TRUE) to be matched in the given character vector. Coerced by as.character() to a character string if possible.
ignore.case	if FALSE, the pattern matching is case sensitive and if TRUE, case is ignored during matching.

Details

These like() and ⁠%like%⁠/⁠%unlike%⁠ functions:

• Are case-insensitive (use ⁠%like_case%⁠/⁠%unlike_case%⁠ for case-sensitive matching)

• Support multiple patterns

• Check if pattern is a valid regular expression and sets fixed = TRUE if not, to greatly improve speed (vectorised over pattern)

• Always use compatibility with Perl unless fixed = TRUE, to greatly improve speed

Using RStudio? The ⁠%like%⁠/⁠%unlike%⁠ functions can also be directly inserted in your code from the Addins menu and can have its own keyboard shortcut like Shift+Ctrl+L or Shift+Cmd+L (see menu Tools > ⁠Modify Keyboard Shortcuts...⁠). If you keep pressing your shortcut, the inserted text will be iterated over ⁠%like%⁠ -> ⁠%unlike%⁠ -> ⁠%like_case%⁠ -> ⁠%unlike_case%⁠.

Value

A logical vector

Source

Idea from the like function from the data.table package, although altered as explained in Details.

See Also

grepl()

Examples

a <- "This is a test"
b <- "TEST"
a %like% b
b %like% a

# also supports multiple patterns
a <- c("Test case", "Something different", "Yet another thing")
b <- c(     "case",           "diff",      "yet")
a %like% b
a %unlike% b

a[1] %like% b
a %like% b[1]

certe-medical-epidemiology/certetoolbox documentation built on April 17, 2025, 3:24 a.m.