Logical functions

Logical functions are based on true or false conditions.

The ifelse function tests whether a specific condition is true, while all the remaining logical functions test whether an attribute corresponds to a specified data type, and can be used on nominal values only.

Note

By default, results are produced as boolean values, consequently all the single values whose data type corresponds to the function return True, otherwise they return False. However, if the optional binary parameter is set to False, for example isInteger($"Score", False), all the single values whose data type corresponds to the function are returned as 1, otherwise as 0.

These functions are useful when users need to change the type of attributes, or they want to identify outliers.

The following functions are available:

• ifelse.

• ifNone.

• isDate.

• isDatetime.

• isFloat.

• isInteger.

• isMonth.

• isQuarter.

• isTime.

• isType.

• isWeek.

See also

Since isDate, isDatetime, isMonth, isQuarter, isTime and isWeek are also Date/Time functions, refer to the date/time function page for the detailed description. Since isFloat, isInteger and isType are also Data functions, refer to the data function page for the detailed description.

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ifelse

The ifelse function checks whether a specific condition is true, and returns the value of iftrue if the condition is true, otherwise it returns the value of iffalse if the condition is false.

Parameters

ifelse(condition, iftrue, iffalse)

Parameter	Description
condition	It is the condition to be satisfied by the function. The condition parameter is mandatory.
iftrue	It is the value or string to be displayed by the function if the condition is verified. The iftrue parameter is mandatory.
iffalse	It is the value or string to be displayed by the function if the condition is not verified. The iffalse parameter is mandatory.

Example - ifelse(condition, iftrue, iffalse)

The following example uses the Bike sales dataset.

• In this example, we want that if the Country is Canada, the attribute is filled with the corresponding Profit values, otherwise if the conditions are not satisfied the string ‘N/A’ is displayed.

• We type the following formula: ifelse($"Country" is 'Canada',$"Profit",'N/A').

• As you can see, the attribute has been populated with the corresponding Profit value when the country is Canada, for all the other Country values an ‘N/A’ is displayed.

Tip

The ifelse function uses a comparison as the first member. Comparison operators have some properties when dealing with None that need to be considered during the use of this function.

• In this example, use cases with the None value in ordinal and nominal attributes, with both the == and is operators.

• However, if we manually modify the Country and the Profit attributes so that their first value is empty, the results change.

• Add two new attributes, one called nom, and one called ord.

• In the nom attribute, type the following formula: ifelse($"Country"=="Canada",True,False).

• As you can see, the None value has been returned as False, as the None value doesn’t satisfy the condition.

• In the ord attribute, type the following formula: ifelse($"Profit" == 590,True,False).

• As you can see, the None value has been returned as None, as with ordinal attributes the == returns the None values.

• If we replace the == operator with is, for both functions the None value will always be returned as a binary value.

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ifNone

The ifNone function fills the attribute’s None values, which satisfy the specified condition, with the desired value. If the condition is not satisfied, the cell is left empty.

Parameters

ifNone(column, condition, iftrue)

Parameter	Description
column	The attribute containing the None values. The iffalse parameter is mandatory
condition	The condition to be satisfied by the function. The condition parameter is mandatory.
iftrue	The value or string to be displayed by the function if the condition is verified.The iftrue parameter is mandatory.

Example - ifNone(column, condition, iftrue)

The following example uses a simple dataset we have created on our own, using an Empty Source task and filling the values randomly through a Data Manager task.

• In this example, we have the Var_3 attribute, which must contain the Var1 values plus the string B replacing the None values if the values in Var_2 are above 3.

• Select the Var_3 attribute and type the following formula ifNone($"Var_1",$"Var_2">3,"B")

• This is the final result. As you can see, in Var_3 attribute, row 4, a B has been added, as in Var_1, row 4 the cell is None and in Var_2, row 4 the value is above 3.