# Substitute Variables (G Dataflow)

Substitutes a formula string by given rules.

## formula

Formula that this node uses to substitute variables.

## substitution rules

Rules for substituting variables.

### parameter name

Name of the parameter that this node looks for in formula.

parameter name can contain any number of valid characters. If parts of the original string represent numbers like 1E-2, the parameter name cannot begin with capital letter E. Otherwise, this node produces unpredictable errors.

### parameter content

Content of the parameter. parameter content must have a one-to-one relation with parameter name.

## error in

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Default: No error

## formula after substitution

Final formula after all substitution rules are performed.

## error out

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

The following table shows an example of the inputs and outputs of this node.

formula substitution rules formula after substitution
ALPHA * cos(t) + beta parameter name parameter content (sin(t))*cos(t)+(2*t*exp(t))
ALPHA sin(t)
beta 2 * t * exp(t)

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported

Web Server: Not supported in VIs that run in a web application