Parse string values as JSON.

Description

Usage

<Expr>$str$json_decode(dtype, ..., infer_schema_length = 100)

Arguments

dtype The dtype to cast the extracted value to. If NULL, the dtype will be inferred from the JSON value.

… These dots are for future extensions and must be empty.

infer_schema_length How many rows to parse to determine the schema. If NULL, all rows are used.

Details

Throw errors if encounter invalid json strings.

Value

A polars expression

Examples

library("polars")

df <- pl$DataFrame(
  json_val = c('{"a":1, "b": true}', NA, '{"a":2, "b": false}')
)
dtype <- pl$Struct(a = pl$Int64, b = pl$Boolean)
df$select(pl$col("json_val")$str$json_decode(dtype))

#> shape: (3, 1)
#> ┌───────────┐
#> │ json_val  │
#> │ ---       │
#> │ struct[2] │
#> ╞═══════════╡
#> │ {1,true}  │
#> │ null      │
#> │ {2,false} │
#> └───────────┘