# Filter rows based on numerical/expression column

# 1 General

**Type:**- Matrix Processing**Heading:**- Filter rows**Source code:**FilterNumericalColumn.cs

# 2 Brief description

Only those rows are kept that have a value in the numerical column fulfilling the equation or inequality relation.

Output: The filtered matrix.

# 3 Parameters

## 3.1 Number of columns

The filtering is based on relations of expression/numerical columns. Up to five columns (default: 1) can be selected. Depending on the number of chosen columns drop down box(es) appear on the pop-up window named “x”, “y”, “z”, “a” and “b”. In these drop down boxes expression/numerical columns can be specified, which can then be used in the relations that should be applied for filtering the matrix.

## 3.2 Number of relations

Up to five relations using the previously specified columns can be included in the filtering process (default:1). Depending on the selected number of relations text fields on the pop-up window appear named “Relation 1”, “Relation 2”, “Relation 3”, “Relation 4” and “Relation 5”.

In each text field a relation for the filtering process can be defined using the variables of the parameter “Number of columns”. For the relations numbers with “.” as decimal point, “+”, “-”, “*”, “/” and “^” as well as scientific notation (e.g. “5.4e-12”) can be used.

## 3.3 Combine through

Defines how the specified relations are combined (default: intersection). Depending on the specified combination mode either rows, which fulfill the “intersection” (default) of the relations are kept or the ones fulfilling the “union”.

## 3.4 Filter mode

The “Filter mode” defines, whether the input matrix will be reduced (“Reduce matrix” = default) or a new categorical column called “Filter” will be generated containing the categories “Keep” and “Discard” (“Filter mode” = “Add categorical column”).