Vectorised Pattern Matching with Keyboard Shortcut

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

Source

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

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.

Value

A logical vector

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%.

Examples

# data.table has a more limited version of %like%, so unload it:
try(detach("package:data.table", unload = TRUE), silent = TRUE)

a <- "This is a test"
b <- "TEST"
a %like% b
#> [1] TRUE
b %like% a
#> [1] FALSE

# also supports multiple patterns
a <- c("Test case", "Something different", "Yet another thing")
b <- c("case", "diff", "yet")
a %like% b
#> [1] TRUE TRUE TRUE
a %unlike% b
#> [1] FALSE FALSE FALSE

a[1] %like% b
#> [1]  TRUE FALSE FALSE
a %like% b[1]
#> [1]  TRUE FALSE FALSE

# \donttest{
# get isolates whose name start with 'Entero' (case-insensitive)
example_isolates[which(mo_name() %like% "^entero"), ]
#> Error: in mo_name(): argument x is missing and no column with info about
#> microorganisms could be found.

if (require("dplyr")) {
  example_isolates %>%
    filter(mo_name() %like% "^ent")
}
#> Error in filter(., mo_name() %like% "^ent"): ℹ In argument: `mo_name() %like% "^ent"`.
#> Caused by error:
#> ! in mo_name(): argument x is missing and no column with info about
#> microorganisms could be found.
# }