Rename

The .rename() method gives one or more columns new names while keeping all columns in the data.

import tidypolars_extra as tp

mtcars = tp.tibble(tp.read_data(fn="tidypolars_extra/data/mtcars.csv", sep=",", silently=True))

small_cars = mtcars.select("mpg", "cyl", "hp")

Renaming with keyword arguments

The simplest way to rename columns is to pass new_name="old_name" as keyword arguments:

small_cars.rename(miles_per_gallon="mpg")

shape: (32, 3)
┌──────────────────┬─────┬─────┐
│ miles_per_gallon  ┆ cyl ┆ hp  │
╞══════════════════╪═════╪═════╡
│ 21.0             ┆ 6   ┆ 110 │
│ 21.0             ┆ 6   ┆ 110 │
│ 22.8             ┆ 4   ┆ 93  │
│ …                ┆ …   ┆ …   │
└──────────────────┴─────┴─────┘

Renaming with a dictionary

You can also pass a dictionary mapping old names to new names:

small_cars.rename({"mpg": "miles_per_gallon", "hp": "horsepower"})

shape: (32, 3)
┌──────────────────┬─────┬────────────┐
│ miles_per_gallon  ┆ cyl ┆ horsepower │
╞══════════════════╪═════╪════════════╡
│ 21.0             ┆ 6   ┆ 110        │
│ 21.0             ┆ 6   ┆ 110        │
│ 22.8             ┆ 4   ┆ 93         │
│ …                ┆ …   ┆ …          │
└──────────────────┴─────┴────────────┘

Rename vs. select

rename keeps all columns while changing specific names. This is equivalent to renaming inside a select while also selecting everything else:

# Using rename (simpler)
small_cars.rename(miles_per_gallon="mpg")

# Equivalent using select + dictionary rename
small_cars.select({"mpg": "miles_per_gallon"}, "cyl", "hp")

Batch renaming with tolower

You can convert all column names to lowercase in one call:

df = tp.tibble(X=[1, 2], Y=[3, 4], Z=[5, 6])
df.rename(tolower=True)

shape: (2, 3)
┌─────┬─────┬─────┐
│ x   ┆ y   ┆ z   │
╞═════╪═════╪═════╡
│ 1   ┆ 3   ┆ 5   │
│ 2   ┆ 4   ┆ 6   │
└─────┴─────┴─────┘