LoopWhile¶
LoopWhile iterates over a set of commands under the control of one or more logical expressions. Since the logical conditions typically depend upon values in the data, commands executed in a LoopWhile cannot be anticipated and expanded in SDTL.
Properties¶
| Name | Type | Description | |
|---|---|---|---|
| Condition | ExpressionBase | 0..1 | Describes a condition required for the next iteration to begin. |
| EndCondition | ExpressionBase | 0..1 | Describes a condition that ends interation. |
| Commands | CommandBase | 1..n | Commands within the loop. |
| Updated | boolean | 0..1 | When TRUE, the loop has been expanded into separate commands. |
Properties Inherited from TransformBase¶
| Name | Type | Description | |
|---|---|---|---|
| ProducesDataframe | DataframeDescription | 0..n | Signify the dataframe which this transform produces. |
| ConsumesDataframe | DataframeDescription | 0..n | Signify the dataframe which this transform acts upon. |
Properties Inherited from CommandBase¶
| Name | Type | Description | |
|---|---|---|---|
| Command | string | 1..1 | The type of command |
| SourceInformation | SourceInformation | 0..n | Information about the source of the command. |
| MessageText | string | 0..n | Adds a message that can be displayed with the command. |
Item Type Hierarchy¶
- CommandBase
- TransformBase
- LoopWhile
Relationships¶
SPSS_example_LoopWhile¶
========= SPSS EXAMPLE ================
LOOP IF (Y GT 10). COMPUTE X=X+1. END LOOP IF (X EQ 5).
``` {“Command”: “LoopWhile”,
- “sourceInformation”: {
- “originalSourceText”: “LOOP IF (Y GT 10).
},
- “Condition”:
{“$type”:”FunctionCallExpression”, “Function”: “gt”, “IsSDTLName”:”True”, “Arguments”: [
{“ArgumentName”: “EXP1”, “ArgumentValue”:
{“$type”: “VariableSymbolExpression”, “VariableName”: “Y”}}, {“ArgumentName”: “EXP2”, “ArgumentValue”:
{“$type”: “NumericConstantExpression”, “Value”: “10”}}
] },
- “EndCondition”:
{“$type”:”FunctionCallExpression”, “Function”: “eq”, “IsSDTLName”:”True”, “Arguments”: [
{“ArgumentName”: “EXP1”, “ArgumentValue”:
{“$type”: “VariableSymbolExpression”, “VariableName”: “X”}}, {“ArgumentName”: “EXP2”, “ArgumentValue”:
{“$type”: “NumericConstantExpression”, “IteratorSymbolName”: “5”}}
] },
- “IteratorCommands:” [
- {“Command”: “compute”,
- “VariableName”:
- {“$type”: “VariableSymbolExpression”, “VariableName”: “X”},
- “Expression”:
- {“$type”:”FunctionCallExpression”,
“Function”: “Addition”, “IsSDTLName”:”True”, “Arguments”: [ {“ArgumentName”: “EXP1”, “ArgumentValue”:
{“$type”: “VariableSymbolExpression”, “VariableName”: “X”}, },{“ArgumentName”: “EXP2”, “ArgumentValue”:
{“$type”: “NumericConstantExpression”, “IteratorSymbolName”: “1”}
]
}
Stata_example_LoopWhile¶
======== Stata EXAMPLE =============== ``` while `i’<40 {
gen newvar`i’ = runiform() local i=`i’+1 }
``` {“Command”: “LoopWhile”,
- “sourceInformation”: {
- “originalSourceText”: “while `i’<40 {
},
- “Condition”:
{“$type”:”FunctionCallExpression”, “Function”: “lt”, “IsSDTLName”:”True”, “Arguments”: [
{“ArgumentName”: “EXP1”, “ArgumentValue”:
{“$type”: “IteratorSymbolExpression”, “IteratorSymbolName”: “i”}}, {“ArgumentName”: “EXP2”, “ArgumentValue”:
{“$type”: “NumericConstantExpression”, “Value”: “40”}}
] },
- “IteratorCommands:” [
- {“Command”: “compute”,
- “VariableName”:
- {“CompositeVariableName”:
- {“Stub”: “newvar”,
- “Postfix”:
- {“$type”: “IteratorSymbolExpression”, “IteratorSymbolName”: “i”} }
},
“Expression”: {“$type”:”FunctionCallExpression”,
“Function”: “random_variable_uniform”, “IsSDTLName”:”True”, “Arguments”: [ {“ArgumentName”: “EXP1”, “ArgumentValue”:
{“$type”: “NumericConstantExpression”, “Value”: “0”}, },{“ArgumentName”: “EXP2”, “ArgumentValue”:
{“$type”: “NumericConstantExpression”, “Value”: “1”}
]
}