Sha256: 8ef940d4d762d4e6c228645e00d9df5f98356c446f14a8e9db65b299daa0a27f
Contents?: true
Size: 1.52 KB
Versions: 47
Compression:
Stored size: 1.52 KB
Contents
module Polars
module Functions
# Return the number of rows in the context.
#
# This is similar to `COUNT(*)` in SQL.
#
# @return [Expr]
#
# @example
# df = Polars::DataFrame.new(
# {
# "a" => [1, 2, nil],
# "b" => [3, nil, nil],
# "c" => ["foo", "bar", "foo"]
# }
# )
# df.select(Polars.len)
# # =>
# # shape: (1, 1)
# # ┌─────┐
# # │ len │
# # │ --- │
# # │ u32 │
# # ╞═════╡
# # │ 3 │
# # └─────┘
#
# @example Generate an index column by using `len` in conjunction with `int_range`.
# df.select([
# Polars.int_range(Polars.len, dtype: Polars::UInt32).alias("index"),
# Polars.all
# ])
# # =>
# # shape: (3, 4)
# # ┌───────┬──────┬──────┬─────┐
# # │ index ┆ a ┆ b ┆ c │
# # │ --- ┆ --- ┆ --- ┆ --- │
# # │ u32 ┆ i64 ┆ i64 ┆ str │
# # ╞═══════╪══════╪══════╪═════╡
# # │ 0 ┆ 1 ┆ 3 ┆ foo │
# # │ 1 ┆ 2 ┆ null ┆ bar │
# # │ 2 ┆ null ┆ null ┆ foo │
# # └───────┴──────┴──────┴─────┘
def len
Utils.wrap_expr(Plr.len)
end
alias_method :length, :len
end
end
Version data entries
47 entries across 47 versions & 1 rubygems