IF Function

TheIFfunction allows you to build if/then/else conditional logic within your transforms.

注意

The IF function is interchangeable with ternary operators. You should use this function instead of ternary construction.

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

Example:

if(State == 'NY','New York, New York!','some other place')

Output: If the value in the State column is NY, return the value New York, New York!. Otherwise, the returned valueis some other place.

Nested IF Example:

You can build IF statements within IF statements as in the following example, in which the second IF is evaluated if the first one evaluates to false:

if(State == 'NY',0.05,if(State=='CA',0.08,0))

A more detailed nested example is available below.

Syntax and Arguments

In the following, if the test expression evaluates to true, the true_expression is executed. Otherwise, the false_expression is executed.

if(test_expression, true_expression,false_expression)

Argument	Required?	Data Type	Description
test_expression	Y	string	Expression that is evaluated. Must resolve to `true` or `false`
true_expression	Y	string	Expression that is executed if `test_expression` is `true`
false_expression	N	string	Expression that is executed if`test_expression`is`false`

All of these expressions can be constants (strings, integers, or any other supported literal value) or sophisticated elements of logic, although the test expression must evaluate to a Boolean value.

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

test_expression

This parameter contains the expression to evaluate. This expression must resolve to a Boolean (true or false) value.

Usage Notes:

Required?	Data Type	Example Value
Yes	String (expression that evaluates to `true` or `false`	(LastName == 'Mouse' && FirstName == 'Mickey')

true_expression, false_expression

The true_expression determines the value or conditional that is generated if the test_expression evaluates to true. If the test is false, then the false_expression applies.

These expressions typically generate output values and can use a combination of literals, functions, and column references.

A true expression is required. You can insert a blank expression ( "").
If a false expression is not provided, false results yield a value of false.

Usage Notes:

Required?	Data Type	Example Value
Yes	String (expression)	See examples below.

Examples

提示

For additional examples, see Common Tasks.

Example - Basic Usage

Example data:

X	Y
true	true
true	false
false	true
false	false

Transformation:

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	if((X == Y), 'yes','no')
Parameter: New column name	'equals'

Results:

Your output looks like the following:

X	Y	equals
true	true	yes
true	false	no
false	true	no
false	false	yes

Example - Stock Quotes

This example demonstrates how you can chain together multiple if/then/else conditions within a single transform step.

You have a set of stock prices that you want to analyze. Based on a set of rules, you want to determine any buy, sell, or hold action to take.

Source:

Ticket	Qty	BuyPrice	CurrentPrice
GOOG	10	705.25	674.5
FB	100	84.00	101.125
AAPL	50	125.25	97.375
MSFT	100	38.875	45.25

Transformation:

You can perform evaluations of this data using the IF function to determine if you want to take action.

To assist in evaluation, you might first want to create columns that contain the cost (Basis) and the current value (CurrentValue) for each stock:

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	(Qty * BuyPrice)
Parameter: New column name	'Basis'

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	(Qty * CurrentPrice)
Parameter: New column name	'CurrentValue'

Now, you can build some rules based on the spread between Basis and CurrentValue.

Single IF version: In this case, the most important action is determining if it is time to sell. The following rule writes a sell notification if the current value is $1000 or more than the cost. Otherwise, no value is written to the action column.

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	if((CurrentValue - 1000 > Basis), 'sell','')
Parameter: New column name	'action'

Nested IF version: But what about buying more? The following transform is an edit to the previous one. In this new version, the sell test is performed, and if false, writes a buy action if the CurrentPrice is within 10% of the BuyPrice.

This second evaluation is performed after the first one, as it replaces the else clause, which did nothing in the previous version. In the Recipe Panel, click the previous transform and edit it, replacing it with the new version:

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	if((CurrentValue - 1000 > Basis), 'sell', if((abs(CurrentValue - Basis) <= (Basis * 0.1)),'buy','hold'))
Parameter: New column name	'action'

If neither test evaluates to true, the written action is hold.

You might want to format some of your columns using dollar formatting, as in the following:

注意

The following formatting inserts a dollar sign ($) in front of the value, which changes the data type to String.

Transformation Name	`Edit column with formula`
Parameter: Columns	BuyPrice
Parameter: Formula	numformat(BuyPrice, '$ ##,###.00')