This notebook describe indexing in Daru::DataFrame with the newly added Categorical Index and other index classes.

require 'daru'

true

Helper function to get a sample dataframe.

def sample_df idx
  Daru::DataFrame.new({
    a: 1..5,
    b: 'a'..'e',
    c: 11..15
  }, index: idx)
end

:sample_df

Categorical Index¶

idx = Daru::CategoricalIndex.new [:a, :b, :a, :b, :c]

#<Daru::CategoricalIndex(5): {a, b, a, b, c}>

df = sample_df idx

Retrive rows by category or position

Note: When index is both a valid category as well as position, then it will treated as category.

df.row[:a, :c]

df.row[0, 1]

Its to fetch vectors and works similar to #row[].

df[:a, :b]

To retrive rows by position.

df.row.at 0, 1, 2

To retrive vectors by position.

df.at 0, 1

Set rows by categories or positions.

Note: In case index is both a valid category and position, it will taken as category.

df.row[:a] = ['x', 'y', 'z']
df

Works similar to #row[]= and is for vectors.

df[:a] = [1]*5
df

Set rows by positions to a given vector

#reset dataframe
df = sample_df idx

df.row.set_at [0, 4], ['x', 'y', 'z']
df

Works similar to #row.at_set

df.set_at [0, 1], [nil]*5
df

Other index classes¶