Extract the first match of JSON string with the provided JSONPath expression

Description

Usage

<Expr>$str$json_path_match(json_path)

Arguments

json_path A valid JSON path query string.

Details

Throw errors if encounter invalid JSON strings. All return value will be cast to String regardless of the original value.

Documentation on JSONPath standard can be found here: https://goessner.net/articles/JsonPath/.

Value

A polars expression

Examples

library("polars")

df <- pl$DataFrame(
  json_val = c('{"a":"1"}', NA, '{"a":2}', '{"a":2.1}', '{"a":true}')
)
df$select(pl$col("json_val")$str$json_path_match("$.a"))

#> shape: (5, 1)
#> ┌──────────┐
#> │ json_val │
#> │ ---      │
#> │ str      │
#> ╞══════════╡
#> │ 1        │
#> │ null     │
#> │ 2        │
#> │ 2.1      │
#> │ true     │
#> └──────────┘