Extract statement

 Extract
   Tgt=Vnn
   Sce=Ann|expression
   Mode=Ave|Sum|SumUp|CountUp|Max|Min|ToCrit|CritMet
   Range=trial_range
   [Crit=min_val,max_val,hits,out_of]

Type conventions and statement syntax are explained in the Glossary.

Extracts a data value from a data array or a combination of data arrays. Wintrack provides storage for 100 data values, referred to as v001-v100.

Parameters...

Tgt
Name parameter indicating the name of the target value. Valid value names are V001 through V100. There is no default for this parameter.

Sce
Name parameter indicating either the name of a source array or an expression of array names or array names and constants. Valid array names are A001 through A100. There is no default for this parameter. If an expression is specified, the arrays are combined element by element before the extraction is performed.

Mode
Radio button parameter indicating the extraction mode to be applied. There is no default, specify one of the following options:

• Ave = calculate the average of the array elements.
• Sum = calculate the sum of the array elements.
• SumUp = same as Sum, but missing values at the beginning of the trial range, or in the middle between trials that have values, are substituted by interpolated values. Missing values trailing at the end of the trial range are ignored.
• CountUp = count trials that have a value. Missing values at the beginning of the trial range or in the middle between trials that have values are counted as well. Missing values trailing at the end of the trial range are not counted.
• Max = pick the element with the maximal value.
• Min = pick the element with the minimal value.
• ToCrit = determine the first trial at which the criterion defined by the parameter Crit is met. If the criterion is never met, the very last trial in the range or the last trial in the range with a value is returned, depending on the settings in Crit..
• CritMet = return 1 if the criterion defined by the parameter Crit is met at least once, else return 0.

Range
Range parameter indicating the range of elements (= trials) to be considered for the extraction. There is no default, you must specify a range.

Crit
Array parameter required to define the criterion for Mode=ToCrit and Mode=CritMet. Four numbers are expected. The first two indicate the minimum and maximum of the value range against which each array element is to be compared. The last two numbers determine how many array elements must fall within the range for the criterion to be met.
Example 1: Crit=0,20,5,6 means 5 out of 6 consecutive trials must have a value between 0 and 20 for the criterion to be met. If the criterion is not met, the last trial in the range with a value is returned.
Example 2: Crit=0,20,-5,-6 gives the same result as Crit=0,20,5,6 if the criterion is met. Else it returns the very last trial in the range.

Note that...

Before you can extract data values you must create at least one data array using the Collapse or Collect statement. You can apply the Extract statement several times to extract different data values from the same data array. The trial range specified using the Range parameter can further be restricted as the variable definition file is later processed using the Analyze Case Document command. Only those trials will be processed that are part of both the command's and the variable definition's trials ranges. If none of the trials to which its definition refers is part of the commands trial range, the variable will not appear in the resulting scrollsheet.

Additional information...

• Managing custom variable definition files provides general information on the management of custom variable definition files.
• The Flowchart of advanced data analysis gives a synopsis of data and variable types.
• There is a topic describing how to build a custom variable definition file.
• There is a list of all available variable definition statements.
• See Analyze Case Document command for basic information on that command.
• Inside case documents provides advanced information on case documents.