plotXY

Purpose

Graphs X vs. Y using Cartesian coordinates.

Format

plotXY([myPlot, ]x, y)

plotXY([myPlot, ]df, formula)

Parameters:

• myPlot (struct) – Optional argument, a plotControl structure.

• x (Nx1 or NxM matrix) – Each column contains the X values for a particular line.

• y (Nx1 or NxM matrix) – Each column contains the Y values for a particular line.

• df (dataframe) – name of the dataframe in memory.

• formula (string) –

  formula string of the model to be plotted. E.g "y ~ X1", y is the name of dependent variable to be plotted on the y-axis X1 is the names of the variable to be plotted on the x-axis;

  E.g "y ~ X1 + by(X2)", by(X2) specifies that the data should be separated into different lines based on the groups defined by X2.

Examples

Basic formula string

// Create string with full path to file name
fname = getGAUSSHome("examples/clotting_time.dat");

// Load all variables from the dataset
clotting_time = loadd(fname);

// Draw plot using formula string to specify variables
plotXY(clotting_time, "lot1 ~ plasma");

Create previous plot with indexing and plot customization

You can create the same plot from the example above without using a formula string as shown below.

// Create string with full path to file name
fname = getGAUSSHome("examples/clotting_time.dat");

// Load all variables from the dataset
clotting_time = loadd(fname);

struct plotControl plt;
plt = plotGetDefaults("xy");

// Set x and y label text
plotSetXLabel(&plt, "plasma", "arial", 12);
plotSetYLabel(&plt, "lot1");

// Draw plot using indexing to specify x and y variables
plotXY(plt, clotting_time[.,"plasma"], clotting_time[.,"lot1"]);

Formula string with multiple y variables

// Create string with full path to file name
fname = getGAUSSHome("examples/clotting_time.dat");

// Load all variables from the dataset
clotting_time = loadd(fname);

// Draw plot using formula string to specify variables
plotXY(clotting_time, "lot1 + lot2 ~ plasma");

Create previous plot with indexing and plot customization

You can create the same plot from the example above without using a formula string as shown below.

// Create string with full path to file name
fname = getGAUSSHome("examples/clotting_time.dat");

// Load all variables from the dataset
clotting_time = loadd(fname);

struct plotControl plt;
plt = plotGetDefaults("xy");

// Set x label text and font
plotSetXLabel(&plt, "plasma", "arial", 12);

plotSetLegend(&plt, "lot1" $| "lot2");

// Draw plot using indexing to specify x and y variables
plotXY(plt, clotting_time[.,"plasma"], clotting_time[.,"lot1" "lot2"]);

Remarks

By default missing values in y will be represented as gaps in the line.

See plotSetXTicInterval() for an example of a time series plot using plotXY().

See also

Functions plotLogX(), plotLogLog(), plotScatter()