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Return the index position of the first substring matching a pattern

Description

Return the index position of the first substring matching a pattern

Usage

<Expr>$str$find(pattern, ..., literal = FALSE, strict = TRUE)

Arguments

pattern A character or something can be coerced to a string Expr of a valid regex pattern, compatible with the regex crate.
… These dots are for future extensions and must be empty.
literal Logical. If TRUE, treat pattern as a literal string, not as a regular expression.
strict Logical. If TRUE (default), raise an error if the underlying pattern is not a valid regex, otherwise mask out with a null value.

Details

To modify regular expression behaviour (such as case-sensitivity) with flags, use the inline (?iLmsuxU) syntax. See the regex crate’s section on grouping and flags for additional information about the use of inline expression modifiers.

Value

A polars expression

See Also

  • $str$start_with(): Check if string values start with a substring.
  • $str$ends_with(): Check if string values end with a substring.
  • $str$contains(): Check if string contains a substring that matches a pattern.

Examples

library("polars")

pl$DataFrame(s = c("AAA", "aAa", "aaa"))$with_columns(
  default_match = pl$col("s")$str$find("Aa"),
  insensitive_match = pl$col("s")$str$find("(?i)Aa")
)

#> shape: (3, 3)
#> ┌─────┬───────────────┬───────────────────┐
#> │ s   ┆ default_match ┆ insensitive_match │
#> │ --- ┆ ---           ┆ ---               │
#> │ str ┆ u32           ┆ u32               │
#> ╞═════╪═══════════════╪═══════════════════╡
#> │ AAA ┆ null          ┆ 0                 │
#> │ aAa ┆ 1             ┆ 0                 │
#> │ aaa ┆ null          ┆ 0                 │
#> └─────┴───────────────┴───────────────────┘