The programmer must take care to check the syntax of the input string and visualize how the string will look during run-time in order to avoid errors. Static content is placed inside of quotes, while variable content is outside of quotes and either entered as a variable name or enclosed within a num2str function. Usually, this string is broken up into static and variable content.

Notice in both of these examples that the eval function takes one string as an input and evaluates it as if it were a command typed into the command line. A for loop is used to save each value in the variable named in each string.

The values that will be saved in the variables are contained inside of a numeric array. In example 2, the variable names are stored as strings that are contained in a cell array. Many beginners in programming struggle with the problem of hiding indices in the names of variables. Matlab is a tool and you can use it the wrong way. In example 1, the date and time are combined into one string which is appended to the end of a generic variable named data. Learn more about char, variable, bad idea Vladislav Kargin: Exactly. In the following examples, we’ll show you how to do these tasks.Įxample 1: Adding the time and date to a variable name > d = datestr(now, 'mmmm_dd_yy_HH_MM_SS') Įxample 2: Creating variables from strings varnames = '= ' num2str(values(k)) ' '])īoth of these examples use the eval function. The best way to accomplish these tasks in Matlab is to use the eval function. You may also have variable names stored in a string or cell array that you want to instantiate as variables. For example, you may want to attach a time or date stamp to the end of a variable name. Thus, your key would become sprintf('%i_%i',x1,x2), and the corresponding value would be whatever it is you want to store.Assume that you want to create a variable in Matlab whose name is contingent on factors that are unknown before the program runs. If you really don't want that, you may be interested in accessing data via key/value pairs in a MAP, a feature which is available in more recent versions of Matlab.

There are many useful ways to store your data in arrays. However, I really have to ask: Are you sure that you want to do that? Because at the moment I cannot imagine an application where would want to create variable names you don't know beforehand, which in turn makes it very hard to write an efficient program. If x1 and x2 are floats, it'll be trickier since a variable name cannot have dots in it, though it would still be possible as long as you replace the dots with something else. Assuming you have a really good reason why you'd want to do that (and assuming x1 and x2 have integer values), you can do this by combining EVAL and SPRINTF.

String to variable name matlab