Implementation:Eventual Inc Daft DataFrame Select

Knowledge Sources	Daft Daft Docs
Domains	Data_Engineering, Data_Transformation
Last Updated	2026-02-08 00:00 GMT

Overview

Concrete tool for projecting specific columns or computed expressions from a DataFrame provided by the Daft library.

Description

The select method on Daft's DataFrame class creates a new DataFrame containing only the specified columns or expressions, similar to a SQL SELECT clause. It accepts column names as strings, Expression objects, or keyword argument projections that create named computed columns. The resulting DataFrame's schema contains only the selected columns in the order specified.

Usage

Use df.select() when you need to narrow a DataFrame to specific columns or compute new columns while dropping all others. This is a method on DataFrame instances and requires no additional imports beyond Daft itself.

Code Reference

Source Location

• Repository: Daft
• File: daft/dataframe/dataframe.py
• Lines: L2009-2041

Signature

def select(self, *columns: ColumnInputType, **projections: Expression) -> DataFrame

Import

import daft

# Method on DataFrame - no separate import needed
df.select("col1", "col2")
df.select(daft.col("x"), daft.col("y") + 1)

I/O Contract

Inputs

Name	Type	Required	Description
*columns	ColumnInputType	Yes	One or more columns to select, specified as strings or Expression objects
**projections	Expression	No	Named keyword projections that create computed columns with the keyword as the column name

Outputs

Name	Type	Description
return	DataFrame	A new DataFrame containing only the selected columns and projections

Usage Examples

Basic Usage

import daft

df = daft.from_pydict({"x": [1, 2, 3], "y": [4, 5, 6], "z": [7, 8, 9]})

# Select specific columns
result = df.select("x", "y")
result.show()
# Output:
# x: [1, 2, 3]
# y: [4, 5, 6]

With Computed Expressions

import daft

df = daft.from_pydict({"x": [1, 2, 3], "y": [4, 5, 6], "z": [7, 8, 9]})

# Select with expressions and computed columns
result = df.select("x", daft.col("y"), daft.col("z") + 1)
result.show()
# Output:
# x: [1, 2, 3]
# y: [4, 5, 6]
# z: [8, 9, 10]

Related Pages

Implements Principle

• Principle:Eventual_Inc_Daft_Column_Selection

Requires Environment

• Environment:Eventual_Inc_Daft_Python_PyArrow_Core