^hash._keys[]
^hash._keys[column name][3.2.2]
The method returns table (object of class table), containing single column with all hash keys listed (since version 3.4.0 the keys in the table are listed in order of putting the elements into the hash, before-the order is not defined).
The name of column-"key" or the column name passed as a parameter.
Example $man[
$.name[Jack]
$.age[22]
$.sex[m]
]
$tab_keys[^man._keys[]]
^tab_keys.save[keys.txt]
…will create file keys.txt with such a table:
key
sex
age
name