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TRUNC Function

Removes all digits to the right of the decimal point for any value. Optionally, you can specify the number of digits to which to round. Input can be an Integer, a Decimal, a column reference, or an expression.

Wrangle vs. SQL: This function is part of Wrangle, a proprietary data transformation language. Wrangle is not SQL. For more information, see Wrangle Language.

Basic Usage

Numeric literal example:

trunc(pi())

Output: Returns the value 3.

Expression example:

trunc(length_in * length_in, 2)

Output:Returns the square of the values in length_in, truncated to two decimal points.

Syntax and Arguments

trunc(numeric_value,integer_value)

Argument

Required?

Data Type

Description

numeric_value

Y

string, decimal, or integer

Name of column or Decimal or Integer literal to apply to the function

integer_value

N

integer

Number of digits to which to truncate.

  • Default is 0, which truncates to the nearest integer.

  • Negative integer values can be applied.

For more information on syntax standards, see Language Documentation Syntax Notes.

numeric_value

Name of the column, numeric literal, or numeric expression.

  • Missing input values generate missing results.

  • Literal numeric values should not be quoted. Quoted values are treated as strings.

  • Multiple columns and wildcards are not supported.

Usage Notes:

Required?

Data Type

Example Value

Yes

String (column reference) or Integer or Decimal literal

2.5

integer_value

Number of digits to which to round the first argument of the function.

  • Positive values values truncate to the right of the decimal point.

  • Negative values truncate to the left of the decimal point.

  • Missing input values generate missing results.

Usage Notes:

Required?

Data Type

Example Value

No

Integer literal

3

Examples

Suggerimento

For additional examples, see Common Tasks.

Example - Basic TRUNC

Source:

RowId

myVal

r01

1.2345

r02

-1.2345

r03

100.000

r04

10.1

r05

50.029

Transformation:

Transformation Name

New formula

Parameter: Formula type

Single row formula

Parameter: Formula

trunc(myVal)

Parameter: New column name

'trunc_myVal'

Transformation Name

New formula

Parameter: Formula type

Single row formula

Parameter: Formula

trunc(myVal,2)

Parameter: New column name

'trunc_myVal2'

Transformation Name

New formula

Parameter: Formula type

Single row formula

Parameter: Formula

trunc(myVal,2)

Parameter: New column name

'trunc_myVal_2'

Results:

RowId

myVal

trunc_myVal

trunc_myVal2

trunc_myVal_2

r01

1.2345

1

1.23

0

r02

-1.2345

-1

-1.23

0

r03

100.000

100

100.00

100

r04

10.1

10

10.1

0

r05

50.029

50

50.02

0

Example - RANDBETWEEN, PI, and TRUNC functions

This example illustrates how you can apply functions to generate random numeric data in your dataset.

Functions:

Item

Description

RANDBETWEEN Function

Generates a random integer between a low and a high number. Two inputs may be Integer or Decimal types, functions returning these types, or column references.

PI Function

The PI function generates the value of pi to 15 decimal places: 3.1415926535897932.

ROUND Function

Rounds input value to the nearest integer. Input can be an Integer, a Decimal, a column reference, or an expression. Optional second argument can be used to specify the number of digits to which to round.

TRUNC Function

Removes all digits to the right of the decimal point for any value. Optionally, you can specify the number of digits to which to round. Input can be an Integer, a Decimal, a column reference, or an expression.

POW Function

Computes the value of the first argument raised to the value of the second argument.

Source:

In the following example, a company produces 10 circular parts, the size of which is measured in each product's radius in inches.

prodId

radius_in

p001

1

p002

2

p003

3

p004

4

p005

5

p006

6

p007

7

p008

8

p009

9

p010

10

Based on the above data, the company wants to generate some additional sizing information for these circular parts, including the generation of two points along each part's circumference where quality stress tests can be applied.

Transformation:

To begin, you can use the following steps to generate the area and circumference for each product, rounded to three decimal points:

Transformation Name

New formula

Parameter: Formula type

Single row formula

Parameter: Formula

ROUND(PI() * (POW(radius_in, 2)), 3)

Parameter: New column name

'area_sqin'

Transformation Name

New formula

Parameter: Formula type

Single row formula

Parameter: Formula

ROUND(PI() * (2 * radius_in), 3)

Parameter: New column name

'circumference_in'

For quality purposes, the company needs two tests points along the circumference, which are generated by calculating two separate random locations along the circumference. Since the RANDBETWEEN function only calculates using Integer values, you must first truncate the values from circumference_in:

Transformation Name

New formula

Parameter: Formula type

Single row formula

Parameter: Formula

TRUNC(circumference_in)

Parameter: New column name

'trunc_circumference_in'

Then, you can calculate the random points using the following:

Transformation Name

New formula

Parameter: Formula type

Single row formula

Parameter: Formula

RANDBETWEEN(0, trunc_circumference_in)

Parameter: New column name

'testPt01_in'

Transformation Name

New formula

Parameter: Formula type

Single row formula

Parameter: Formula

RANDBETWEEN(0, trunc_circumference_in)

Parameter: New column name

'testPt02_in'

Results:

After the trunc_circumference_in column is dropped, the data should look similar to the following:

prodId

radius_in

area_sq_in

circumference_in

testPt01_in

testPt02_in

p001

1

3.142

6.283

5

5

p002

2

12.566

12.566

3

3

p003

3

28.274

18.850

13

13

p004

4

50.265

25.133

24

24

p005

5

78.540

31.416

0

0

p006

6

113.097

37.699

15

15

p007

7

153.938

43.982

11

11

p008

8

201.062

50.265

1

1

p009

9

254.469

56.549

29

29

p010

10

314.159

62.832

21

21