Name=Value in Function Calls
Since R2021a
MATLAB supports two syntaxes for passing name-value arguments.
plot(x,y,LineWidth=2) name=value syntax
plot(x,y,"LineWidth",2) comma-separated syntax
Use the name=value syntax to help identify name-value arguments for functions and to clearly
distinguish names from values in lists of name-value arguments.
Most functions and methods support both syntaxes, but there are some limitations on where and how
the name=value syntax can be used:
• Mixing name,value and name=value syntaxes: The recommended practice is to use only one
syntax in any given function call. However, if you do mix name=value and name,value syntaxes
in a single call, all name=value arguments must appear after the name,value arguments. For
example, plot(x,y,"Color","red",LineWidth=2) is a valid combination, but
plot(x,y,Color="red","LineWidth",2) errors.
• Using positional arguments after name-value arguments: Some functions have positional
arguments that appear after name-value arguments. For example, this call to the verifyEqual
method uses the RelTol name-value argument, followed by a string input:
verifyEqual(testCase,1.5,2,"RelTol",0.1,...
"Difference exceeds relative tolerance.")
Using the name=value syntax (RelTol=0.1) causes the statement to error. In cases where a
positional argument follows name-value arguments, use the name,value syntax.
• Names that are invalid variable names: Name-value arguments with names that are invalid
MATLAB variable names cannot be used with the name=value syntax. See “Variable Names” on
page 1-5 for more info. For example, a name-value argument like "allow-empty",true errors
if passed as allow-empty=true. Use the name,value syntax in these cases.
Function authors do not need to code differently to support both the name,value and name=value
syntaxes. For information on authoring functions that accept name-value arguments, see “Name-Value
Arguments” on page 26-10.
Name=Value in Function Calls
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