stem - Plot discrete sequence data - MATLAB (original) (raw)

Plot discrete sequence data

Syntax

Description

Vector and Matrix Data

stem([Y](#btrw%5Fxi-1-Y)) plots the data sequence, Y, as stems that extend from a baseline along the _x_-axis. The data values are indicated by circles terminating each stem.

• If Y is a vector, then the _x_-axis scale ranges from 1 to length(Y).
• If Y is a matrix, then stem plots all elements in a row against the same x value, and the _x_-axis scale ranges from 1 to the number of rows in Y.

example

stem([X](#btrw%5Fxi-1-X),[Y](#btrw%5Fxi-1-Y)) plots the data sequence, Y, at values specified by X. The X and Y inputs must be vectors or matrices of the same size. Additionally, X can be a row or column vector and Y must be a matrix with length(X) rows.

• If X and Y are both vectors, then stem plots entries in Y against corresponding entries in X.
• If X is a vector and Y is a matrix, then stem plots each column of Y against the set of values specified by X, such that all elements in a row of Y are plotted against the same value.
• If X and Y are both matrices, then stem plots columns of Y against corresponding columns of X.

example

stem(___,`"filled"`) fills the circles. Use this option with any of the input argument combinations in the previous syntaxes.

example

stem(___,[LineSpec](#btrw%5Fxi-1%5Fsep%5Fmw%5F3a76f056-2882-44d7-8e73-c695c0c54ca8)) specifies the line style, marker symbol, and color.

example

Table Data

stem([tbl](#btrw%5Fxi-1%5Fsep%5Fmw%5F1f5b8358-45d8-4c4d-8a0d-17e2da07c841),[yvar](#mw%5F0ee057c8-e493-4a58-960a-74669863583d)) plots the specified variable from the table against the row indices of the table. If the table is a timetable, the specified variable is plotted against the row times of the timetable. To plot one set of _y_-values, specify one variable for yvar. To plot multiple sets of_y_-values, specify multiple variables foryvar. (since R2022b)

example

stem([tbl](#btrw%5Fxi-1%5Fsep%5Fmw%5F1f5b8358-45d8-4c4d-8a0d-17e2da07c841),[xvar](#mw%5F4f7f22fd-b61d-4bb8-8434-510ae53615c5),[yvar](#mw%5F0ee057c8-e493-4a58-960a-74669863583d)) plots the variables xvar and yvar from the table tbl. You can specify one or multiple variables forxvar and yvar. If both arguments specify multiple variables, they must specify the same number of variables. (since R2022b)

example

Additional Options

stem(___,[Name,Value](#namevaluepairarguments)) modifies the stem chart using one or more Name,Value pair arguments.

example

stem([ax](#btrw%5Fxi-1-ax),___) plots into the axes specified by ax instead of into the current axes (gca). The option, ax, can precede any of the input argument combinations in the previous syntaxes.

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[h](#btrw%5Fxi-1-h) = stem(___) returns a vector of Stem objects in h. Use h to modify the stem chart after it is created.

example

Examples

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Plot Single Data Series

Create a stem plot of 50 data values between -2π and 2π.

figure Y = linspace(-2pi,2pi,50); stem(Y)

Data values are plotted as stems extending from the baseline and terminating at the data value. The length of Y automatically determines the position of each stem on the _x_-axis.

Plot Multiple Data Series

Plot two data series using a two-column matrix.

figure X = linspace(0,2pi,50)'; Y = [cos(X), 0.5sin(X)]; stem(Y)

Each column of Y is plotted as a separate series, and entries in the same row of Y are plotted against the same x value. The number of rows in Y automatically generates the position of each stem on the _x_-axis.

Plot Single Data Series at Specified x values

Plot 50 data values of cosine evaluated between 0 and 2π and specify the set of x values for the stem plot.

figure X = linspace(0,2*pi,50)'; Y = cos(X); stem(X,Y)

The first vector input determines the position of each stem on the _x_-axis.

Plot Multiple Data Series at Specified x values

Plot 50 data values of sine and cosine evaluated between 0 and 2π and specify the set of x values for the stem plot.

figure X = linspace(0,2pi,50)'; Y = [cos(X), 0.5sin(X)]; stem(X,Y)

The vector input determines the _x_-axis positions for both data series.

Plot Multiple Data Series at Unique Sets of x values

Plot 50 data values of sine and cosine evaluated at different sets of x values. Specify the corresponding sets of x values for each series.

figure x1 = linspace(0,2pi,50)'; x2 = linspace(pi,3pi,50)'; X = [x1, x2]; Y = [cos(x1), 0.5*sin(x2)]; stem(X,Y)

Each column of X is plotted against the corresponding column of Y.

Fill in Plot Markers

Create a stem plot and fill in the circles that terminate each stem.

X = linspace(0,10,20)'; Y = (exp(0.25*X)); stem(X,Y,'filled')

Specify Stem and Marker Options

Create a stem plot and set the line style to a dotted line, the marker symbols to diamonds, and the color to red using the LineSpec option.

figure X = linspace(0,2*pi,50)'; Y = (exp(X).*sin(X)); stem(X,Y,':diamondr')

To color the inside of the diamonds, use the 'fill' option.

Specify Additional Stem and Marker Options

Create a stem plot and set the line style to a dot-dashed line, the marker face color to red, and the marker edge color to green using Name,Value pair arguments.

figure X = linspace(0,2pi,25)'; Y = (cos(2X)); stem(X,Y,'LineStyle','-.',... 'MarkerFaceColor','red',... 'MarkerEdgeColor','green')

The stem remains the default color.

Plot Data from a Table

Since R2022b

A convenient way to plot data from a table is to pass the table to the stem function and specify the variables to plot.

Read the first 100 rows and 7 columns of weather.csv as a timetable tbl. Then display the first three rows of the table.

tbl = readtimetable("weather.csv","Range",[1 1 101 7]); head(tbl,3)

        Time            WindDirection    WindSpeed    Humidity    Temperature    RainInchesPerMinute    CumulativeRainfall
____________________    _____________    _________    ________    ___________    ___________________    __________________

25-Oct-2021 00:00:09         46               1          84          49.2                 0                     0         
25-Oct-2021 00:01:09         45             1.6          84          49.2                 0                     0         
25-Oct-2021 00:02:09         36             2.2          84          49.2                 0                     0         

Plot the row times on the _x_-axis and the CumulativeRainfall variable on the _y_-axis. When you plot data from a timetable, the row times are plotted on the _x_-axis by default. Thus, you do not need to specify the Time variable. Return the Stem object as h. Notice that the axis labels match the variable names.

h = stem(tbl,"CumulativeRainfall");

Change the color of the plot to purple by setting the Color property.

Plot Multiple Table Variables on One Axis

Since R2022b

Create vectors x, y1, and y2, and use them to create a table. Plot the y1 and y2 variables against the x variable, and use the axis padded command so that the stems do not overlap with the plot box. Then add a legend, and notice that the legend labels match the table variable names.

x = (0:0.1:2.9)'; y1 = cos(x); y2 = sin(x); tbl = table(x,y1,y2); stem(tbl,"x",["y1","y2"]);

% Pad axes and add a legend axis padded legend

Alternatively, you can omit the x variable and plot the y1 and y2 variables against the row indices of the table.

stem(tbl,["y1","y2"]); axis padded legend

Specify Axes for Stem Plot

You can display a tiling of plots using the tiledlayout and nexttile functions. Call the tiledlayout function to create a 2-by-1 tiled chart layout. Call the nexttile function to create the axes objects ax1 and ax2. Create separate stem plots in the axes by specifying the axes object as the first argument to stem.

x = 0:25; y1 = exp(0.1x); y2 = -exp(.05x); tiledlayout(2,1)

% Top plot ax1 = nexttile; stem(ax1,x,y1)

% Bottom plot ax2 = nexttile; stem(ax2,x,y2)

Modify Stem Series After Creation

Create a 3-D stem plot and return the stem series object.

X = linspace(0,2); Y = X.^3; Z = exp(X).*cos(Y); h = stem3(X,Y,Z,'filled');

Change the color to magenta and set the marker face color to yellow. Use view to adjust the angle of the axes in the figure. Use dot notation to set properties.

h.Color = 'm'; h.MarkerFaceColor = 'y'; view(-10,35)

Adjust Baseline Properties

Create a stem plot and change properties of the baseline.

X = linspace(0,2pi,50); Y = exp(0.3X).sin(3X); h = stem(X,Y);

Change the line style of the baseline. Use dot notation to set properties.

hbase = h.BaseLine; hbase.LineStyle = '--';

Hide the baseline by setting its Visible property to 'off'.

Change Baseline Level

Create a stem plot with a baseline level at 2.

X = linspace(0,2pi,50)'; Y = (exp(0.3X).sin(3X)); stem(X,Y,'BaseValue',2);

Input Arguments

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Y — Data sequence to display

vector or matrix

Data sequence to display, specified as a vector or matrix. When Y is a vector, stem creates one Stem object. When Y is a matrix, stem creates a separate Stem object for each column.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | categorical | datetime | duration

X — Locations to plot data values in Y

vector or matrix

Locations to plot data values in Y, specified as a vector or matrix. When Y is a vector, X must be a vector of the same size. When Y is a matrix, X must be a matrix of the same size, or a vector whose length equals the number of rows in Y.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | categorical | datetime | duration

LineSpec — Line style, marker, and color

string scalar | character vector

Line style, marker, and color, specified as a string scalar or character vector containing symbols. The symbols can appear in any order. You do not need to specify all three characteristics (line style, marker, and color). For example, if you omit the line style and specify the marker, then the plot shows only the marker and no line.

Example: "--or" is a red dashed line with circle markers.

Line Style	Description	Resulting Line
"-"	Solid line
"--"	Dashed line
":"	Dotted line
"-."	Dash-dotted line

Marker	Description	Resulting Marker
"o"	Circle
"+"	Plus sign
"*"	Asterisk
"."	Point
"x"	Cross
"_"	Horizontal line
"|"	Vertical line
"square"	Square
"diamond"	Diamond
"^"	Upward-pointing triangle
"v"	Downward-pointing triangle
">"	Right-pointing triangle
"<"	Left-pointing triangle
"pentagram"	Pentagram
"hexagram"	Hexagram

Color Name	Short Name	RGB Triplet	Appearance
"red"	"r"	[1 0 0]
"green"	"g"	[0 1 0]
"blue"	"b"	[0 0 1]
"cyan"	"c"	[0 1 1]
"magenta"	"m"	[1 0 1]
"yellow"	"y"	[1 1 0]
"black"	"k"	[0 0 0]
"white"	"w"	[1 1 1]

tbl — Source table

table | timetable

Source table containing the data to plot, specified as a table or a timetable.

yvar — Table variables containing _y_-coordinates

string array | character vector | cell array | pattern | numeric scalar or vector | logical vector | vartype()

Table variables containing the _y_-coordinates, specified using one of the indexing schemes from the table.

The table variables you specify can contain numeric, categorical, datetime, or duration values. If xvar andyvar both specify multiple variables, the number of variables must be the same.

Example: stem(tbl,"x",["y1","y2"]) specifies the table variables named y1 and y2 for the_y_-coordinates.

Example: stem(tbl,"x",2) specifies the second variable for the _y_-coordinates.

Example: stem(tbl,"x",vartype("numeric")) specifies all numeric variables for the _y_-coordinates.

xvar — Table variables containing _x_-coordinates

string array | character vector | cell array | pattern | numeric scalar or vector | logical vector | vartype()

Table variables containing the _x_-coordinates, specified using one of the indexing schemes from the table.

The table variables you specify can contain numeric, categorical, datetime, or duration values. If xvar andyvar both specify multiple variables, the number of variables must be the same.

Example: stem(tbl,["x1","x2"],"y") specifies the table variables named x1 and x2 for the_x_-coordinates.

Example: stem(tbl,2,"y") specifies the second variable for the _x_-coordinates.

Example: stem(tbl,vartype("numeric"),"y") specifies all numeric variables for the _x_-coordinates.

ax — Axes object

Axes object

Axes object. If you do not specify the axes, then stem plots into the current axes.

Name-Value Arguments

Specify optional pairs of arguments asName1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: "LineStyle",":","MarkerFaceColor","red" plots the stem as a dotted line and colors the marker face red.

The Stem properties listed here are only a subset. For a complete list, see Stem Properties.

Line style, specified as one of the options listed in this table.

Line Style	Description	Resulting Line
"-"	Solid line
"--"	Dashed line
":"	Dotted line
"-."	Dash-dotted line
"none"	No line	No line

Line width, specified as a positive value in points, where 1 point = 1/72 of an inch. If the line has markers, then the line width also affects the marker edges.

The line width cannot be thinner than the width of a pixel. If you set the line width to a value that is less than the width of a pixel on your system, the line displays as one pixel wide.

Color — Stem color

[0 0 0] (default) | RGB triplet | hexadecimal color code | "r" | "g" | "b" | ...

Stem color, specified as an RGB triplet, a hexadecimal color code, a color name, or a short name.

For a custom color, specify an RGB triplet or a hexadecimal color code.

• An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1], for example, [0.4 0.6 0.7].
• A hexadecimal color code is a string scalar or character vector that starts with a hash symbol (#) followed by three or six hexadecimal digits, which can range from 0 to F. The values are not case sensitive. Therefore, the color codes"#FF8800","#ff8800","#F80", and"#f80" are equivalent.

Alternatively, you can specify some common colors by name. This table lists the named color options, the equivalent RGB triplets, and hexadecimal color codes.

Color Name	Short Name	RGB Triplet	Hexadecimal Color Code	Appearance
"red"	"r"	[1 0 0]	"#FF0000"
"green"	"g"	[0 1 0]	"#00FF00"
"blue"	"b"	[0 0 1]	"#0000FF"
"cyan"	"c"	[0 1 1]	"#00FFFF"
"magenta"	"m"	[1 0 1]	"#FF00FF"
"yellow"	"y"	[1 1 0]	"#FFFF00"
"black"	"k"	[0 0 0]	"#000000"
"white"	"w"	[1 1 1]	"#FFFFFF"
"none"	Not applicable	Not applicable	Not applicable	No color

Here are the RGB triplets and hexadecimal color codes for the default colors MATLAB® uses in many types of plots.

RGB Triplet	Hexadecimal Color Code	Appearance
[0 0.4470 0.7410]	"#0072BD"
[0.8500 0.3250 0.0980]	"#D95319"
[0.9290 0.6940 0.1250]	"#EDB120"
[0.4940 0.1840 0.5560]	"#7E2F8E"
[0.4660 0.6740 0.1880]	"#77AC30"
[0.3010 0.7450 0.9330]	"#4DBEEE"
[0.6350 0.0780 0.1840]	"#A2142F"

Example: "blue"

Example: [0 0 1]

Example: "#0000FF"

Marker — Marker symbol

"o" (default) | "+" | "*" | "." | "x" | ...

Marker symbol, specified as one of the markers listed in this table.

Marker	Description	Resulting Marker
"o"	Circle
"+"	Plus sign
"*"	Asterisk
"."	Point
"x"	Cross
"_"	Horizontal line
"|"	Vertical line
"square"	Square
"diamond"	Diamond
"^"	Upward-pointing triangle
"v"	Downward-pointing triangle
">"	Right-pointing triangle
"<"	Left-pointing triangle
"pentagram"	Pentagram
"hexagram"	Hexagram
"none"	No markers	Not applicable

Example: "+"

Example: "diamond"

Marker size, specified as a positive value in points, where 1 point = 1/72 of an inch.

Marker outline color, specified as "auto", an RGB triplet, a hexadecimal color code, a color name, or a short name. The default value of"auto" uses the same color as the Color property.

For a custom color, specify an RGB triplet or a hexadecimal color code.

• An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1], for example, [0.4 0.6 0.7].
• A hexadecimal color code is a string scalar or character vector that starts with a hash symbol (#) followed by three or six hexadecimal digits, which can range from 0 to F. The values are not case sensitive. Therefore, the color codes"#FF8800","#ff8800","#F80", and"#f80" are equivalent.

Alternatively, you can specify some common colors by name. This table lists the named color options, the equivalent RGB triplets, and hexadecimal color codes.

Color Name	Short Name	RGB Triplet	Hexadecimal Color Code	Appearance
"red"	"r"	[1 0 0]	"#FF0000"
"green"	"g"	[0 1 0]	"#00FF00"
"blue"	"b"	[0 0 1]	"#0000FF"
"cyan"	"c"	[0 1 1]	"#00FFFF"
"magenta"	"m"	[1 0 1]	"#FF00FF"
"yellow"	"y"	[1 1 0]	"#FFFF00"
"black"	"k"	[0 0 0]	"#000000"
"white"	"w"	[1 1 1]	"#FFFFFF"
"none"	Not applicable	Not applicable	Not applicable	No color

Here are the RGB triplets and hexadecimal color codes for the default colors MATLAB uses in many types of plots.

RGB Triplet	Hexadecimal Color Code	Appearance
[0 0.4470 0.7410]	"#0072BD"
[0.8500 0.3250 0.0980]	"#D95319"
[0.9290 0.6940 0.1250]	"#EDB120"
[0.4940 0.1840 0.5560]	"#7E2F8E"
[0.4660 0.6740 0.1880]	"#77AC30"
[0.3010 0.7450 0.9330]	"#4DBEEE"
[0.6350 0.0780 0.1840]	"#A2142F"

Marker fill color, specified as "auto", an RGB triplet, a hexadecimal color code, a color name, or a short name. The "auto" option uses the same color as the Color property of the parent axes. If you specify"auto" and the axes plot box is invisible, the marker fill color is the color of the figure.

For a custom color, specify an RGB triplet or a hexadecimal color code.

• An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1], for example, [0.4 0.6 0.7].
• A hexadecimal color code is a string scalar or character vector that starts with a hash symbol (#) followed by three or six hexadecimal digits, which can range from 0 to F. The values are not case sensitive. Therefore, the color codes"#FF8800","#ff8800","#F80", and"#f80" are equivalent.

Alternatively, you can specify some common colors by name. This table lists the named color options, the equivalent RGB triplets, and hexadecimal color codes.

Color Name	Short Name	RGB Triplet	Hexadecimal Color Code	Appearance
"red"	"r"	[1 0 0]	"#FF0000"
"green"	"g"	[0 1 0]	"#00FF00"
"blue"	"b"	[0 0 1]	"#0000FF"
"cyan"	"c"	[0 1 1]	"#00FFFF"
"magenta"	"m"	[1 0 1]	"#FF00FF"
"yellow"	"y"	[1 1 0]	"#FFFF00"
"black"	"k"	[0 0 0]	"#000000"
"white"	"w"	[1 1 1]	"#FFFFFF"
"none"	Not applicable	Not applicable	Not applicable	No color

Here are the RGB triplets and hexadecimal color codes for the default colors MATLAB uses in many types of plots.

RGB Triplet	Hexadecimal Color Code	Appearance
[0 0.4470 0.7410]	"#0072BD"
[0.8500 0.3250 0.0980]	"#D95319"
[0.9290 0.6940 0.1250]	"#EDB120"
[0.4940 0.1840 0.5560]	"#7E2F8E"
[0.4660 0.6740 0.1880]	"#77AC30"
[0.3010 0.7450 0.9330]	"#4DBEEE"
[0.6350 0.0780 0.1840]	"#A2142F"

Output Arguments

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h — Stem objects

Stem objects

Stem objects. These are unique identifiers, which you can use to modify the properties of a specific Stem object after it is created.

Extended Capabilities

GPU Arrays

Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.

The stem function supports GPU array input with these usage notes and limitations:

• This function accepts GPU arrays, but does not run on a GPU.

For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Distributed Arrays

Partition large arrays across the combined memory of your cluster using Parallel Computing Toolbox™.

Usage notes and limitations:

• This function operates on distributed arrays, but executes in the client MATLAB.

For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).

Version History

Introduced before R2006a

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R2024b: _x_-axis limits are padded by default

Stem plots now have padding on the right and left sides of the_x_-axis to prevent overlap with the edges of the plot box.

R2022b: Pass tables directly to stem

Create plots by passing a table to the stem function followed by the variables you want to plot. When you specify your data as a table, the axis labels and the legend (if present) are automatically labeled using the table variable names.