IF Function
TheIF
function allows you to build if/then/else conditional logic within your transforms.
注記
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_expression | Y | string | Expression that is executed if |
false_expression | N | string | Expression that is executed if |
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 | (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
ヒント
For additional examples, see Common Tasks.
Example - Basic Usage
Example data:
X | Y |
---|---|
true | true |
true | false |
false | true |
false | false |
Transformation:
Transformation Name | |
---|---|
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 | |
---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | (Qty * BuyPrice) |
Parameter: New column name | 'Basis' |
Transformation Name | |
---|---|
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 $1000 or more than the cost. Otherwise, no value is written to the action column.
Transformation Name | |
---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | if((CurrentValue - 1000 > Basis), 'sell','') |
Parameter: New column name | 'action' |
Nested IF
version: But what about buying more? The following transform is an edit to the previous one. In this new version, the sell test is performed, and if false
, writes a buy
action if the CurrentPrice
is within 10% of the BuyPrice
.
This second evaluation is performed after the first one, as it replaces the else clause, which did nothing in the previous version. In the Recipe Panel, click the previous transform and edit it, replacing it with the new version:
Transformation Name | |
---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | if((CurrentValue - 1000 > Basis), 'sell', if((abs(CurrentValue - Basis) <= (Basis * 0.1)),'buy','hold')) |
Parameter: New column name | 'action' |
If neither test evaluates to true
, the written action is hold
.
You might want to format some of your columns using dollar formatting, as in the following:
注記
The following formatting inserts a dollar sign ($) in front of the value, which changes the data type to String.
Transformation Name | |
---|---|
Parameter: Columns | BuyPrice |
Parameter: Formula | numformat(BuyPrice, '$ ##,###.00') |
Results:
After moving your columns, your dataset should look like the following, if you completed the number formatting steps:
Ticket | Qty | BuyPrice | CurrentPrice | Basis | CurrentValue | action |
---|---|---|---|---|---|---|
GOOG | 10 | 705.25 | $ 674.50 | $ 7,052.50 | $ 6,745.00 | buy |
FB | 100 | 84.00 | $ 101.13 | $ 8,400.00 | $ 10,112.50 | sell |
AAPL | 50 | 125.25 | $ 97.38 | $ 6,262.50 | $ 4,868.75 | hold |
MSFT | 100 | 38.88 | $ 45.25 | $ 3,887.50 | $ 4,525.00 | hold |