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Polars R Package

to_date

Convert a String column into a Date column

Source code

Description

Convert a String column into a Date column

Usage

<Expr>$str$to_date(format = NULL, ..., strict = TRUE, exact = TRUE, cache = TRUE)

Arguments

`format`	Format to use for conversion. Refer to the chrono crate documentation for the full specification. Example: `“%Y-%m-%d %H:%M:%S”`. If `NULL` (default), the format is inferred from the data. Notice that time zone `%Z` is not supported and will just ignore timezones. Numeric time zones like `%z` or `%:z` are supported.
`…`	Not used.
`strict`	If `TRUE` (default), raise an error if a single string cannot be parsed. If `FALSE`, produce a polars `null`.
`exact`	If `TRUE` (default), require an exact format match. If `FALSE`, allow the format to match anywhere in the target string. Conversion to the Time type is always exact. Note that using `exact = FALSE` introduces a performance penalty - cleaning your data beforehand will almost certainly be more performant.
`cache`	Use a cache of unique, converted dates to apply the datetime conversion.

Format

Format to use for conversion. Refer to the chrono crate documentation for the full specification. Example: “%Y-%m-%d”. If NULL (default), the format is inferred from the data.

Value

Expr of Date type

See Also

\$str$strptime()

Examples

library(polars)

s = as_polars_series(c("2020/01/01", "2020/02/01", "2020/03/01"))

s$str$to_date()

#> polars Series: shape: (3,)
#> Series: '' [date]
#> [
#>  2020-01-01
#>  2020-02-01
#>  2020-03-01
#> ]

# by default, this errors if some values cannot be converted
s = as_polars_series(c("2020/01/01", "2020 02 01", "2020-03-01"))
try(s$str$to_date())

#> Error : Execution halted with the following contexts
#>    0: In R: in $select()
#>    0: During function call [.main()]
#>    1: Encountered the following error in Rust-Polars:
#>          conversion from `str` to `date` failed in column '' for 1 out of 3 values: ["2020 02 01"]
#> 
#>       You might want to try:
#>       - setting `strict=False` to set values that cannot be converted to `null`
#>       - using `str.strptime`, `str.to_date`, or `str.to_datetime` and providing a format string

s$str$to_date(strict = FALSE)

#> polars Series: shape: (3,)
#> Series: '' [date]
#> [
#>  2020-01-01
#>  null
#>  2020-03-01
#> ]