char combining error: Matrix dimensions must agree. - SIMPLE SCRIPT

I am importing a large quantity of .dat files. I get this error even when running an apparently simple code:

clear all
clc

n='20000'
u='u2DSolution'+n+'.dat'

Error:
Matrix dimensions must agree.

Error in Untitled (line 5)
u='u2DSolution'+n+'.dat'

[Stephen23]

"I get this error even when running an apparently simple code:"

It is simple code: you are adding the character codes of some character vectors. Just like with numeric vectors if they have incompatible sizes then you will get an error.

You probably want to concatenate those character vectors, rather than add their chracter codes.

Answer 1

[Steven Lord]

The + operator performs concatenation if one of the things you're "adding" together is a string array.

n = 20000;
u = "u2DSolution" + n + ".dat"

The + operator when called with char arrays (no string arrays involved) performs arithmetic if the inputs are compatibly sized.

b = 'a' + 1 % double('b') which you can check with
characterB = char(b)

Answer 2

[madhan ravi]

n='20000'
u=['u2DSolution',n,'.dat']