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Select all columns with alphanumeric names (e.g. only letters and the digits 0-9)

Description

Select all columns with alphanumeric names (e.g. only letters and the digits 0-9)

Usage

cs__alphanumeric(ascii_only = FALSE, ..., ignore_spaces = FALSE)

Arguments

ascii_only Indicate whether to consider only ASCII alphabetic characters, or the full Unicode range of valid letters (accented, idiographic, etc).
… These dots are for future extensions and must be empty.
ignore_spaces Indicate whether to ignore the presence of spaces in column names; if so, only the other (non-space) characters are considered.

Details

Matching column names cannot contain any non-alphabetic characters. Note that the definition of “alphabetic” consists of all valid Unicode alphabetic characters (p{Alphabetic}) and digit characters (d) by default; this can be changed by setting ascii_only = TRUE.

Value

A Polars selector

See Also

cs for the documentation on operators supported by Polars selectors.

Examples

library("polars")

df <- pl$DataFrame(
  `1st_col` = c(100, 200, 300),
  flagged = c(TRUE, FALSE, TRUE),
  `00prefix` = c("01:aa", "02:bb", "03:cc"),
  `last col` = c("x", "y", "z")
)

# Select columns with alphanumeric names:
df$select(cs$alphanumeric())

#> shape: (3, 2)
#> ┌─────────┬──────────┐
#> │ flagged ┆ 00prefix │
#> │ ---     ┆ ---      │
#> │ bool    ┆ str      │
#> ╞═════════╪══════════╡
#> │ true    ┆ 01:aa    │
#> │ false   ┆ 02:bb    │
#> │ true    ┆ 03:cc    │
#> └─────────┴──────────┘

df$select(cs$alphanumeric(ignore_spaces = TRUE))

#> shape: (3, 3)
#> ┌─────────┬──────────┬──────────┐
#> │ flagged ┆ 00prefix ┆ last col │
#> │ ---     ┆ ---      ┆ ---      │
#> │ bool    ┆ str      ┆ str      │
#> ╞═════════╪══════════╪══════════╡
#> │ true    ┆ 01:aa    ┆ x        │
#> │ false   ┆ 02:bb    ┆ y        │
#> │ true    ┆ 03:cc    ┆ z        │
#> └─────────┴──────────┴──────────┘

# Select all columns except for those with alphanumeric names:
df$select(!cs$alphanumeric())

#> shape: (3, 2)
#> ┌─────────┬──────────┐
#> │ 1st_col ┆ last col │
#> │ ---     ┆ ---      │
#> │ f64     ┆ str      │
#> ╞═════════╪══════════╡
#> │ 100.0   ┆ x        │
#> │ 200.0   ┆ y        │
#> │ 300.0   ┆ z        │
#> └─────────┴──────────┘

df$select(!cs$alphanumeric(ignore_spaces = TRUE))

#> shape: (3, 1)
#> ┌─────────┐
#> │ 1st_col │
#> │ ---     │
#> │ f64     │
#> ╞═════════╡
#> │ 100.0   │
#> │ 200.0   │
#> │ 300.0   │
#> └─────────┘