polars.DataFrame.melt#

Unpivot a DataFrame from wide to long format.

Optionally leaves identifiers set.

This function is useful to massage a DataFrame into a format where one or more columns are identifier variables (id_vars) while all other columns, considered measured variables (value_vars), are “unpivoted” to the row axis leaving just two non-identifier columns, ‘variable’ and ‘value’.

Deprecated since version 1.0.0: Please use unpivot() instead.

Parameters:

id_vars: Column(s) or selector(s) to use as identifier variables.
value_vars: Column(s) or selector(s) to use as values variables; if value_vars is empty all columns that are not in id_vars will be used.
variable_name: Name to give to the variable column. Defaults to “variable”
value_name: Name to give to the value column. Defaults to “value”