Loop for repeated file input if error

clc
clear
close all

%Input for data file name
myFilename = input('Please enter data file name.(Case sensitive):''s');
myFilename1 = 'myFilename';

%While loop if datafile does not exist
while <filenamedoesnotexist>
    myFilename = input('Please enter the correct data file name(Case sensitive). Ensure spelling is correct:');
myFilename1 = 'myFilename';
end
%Import data from excel file
[times,Company_name,~] = xlsread(myFilename1)

I want Matlab to create a while loop if the file name entered brings in an error like file does not exist until user writes correct file name.

[stozaki]

Your while loop has the wrong syntax.

Define a condition equivalent to expression.

while

while expression
    statements
end

[Walter Roberson]

You should use the 's' option on input()

And see exist()

[Pallav Patel]

Thank you Robertson. That is actually a rough view of what I am trying to create. The input that the user types is an excel file name that will later be imported using the xlsread() function. If MATLAB does not recognise the file within it directory it usually brings an error. I would like to create a loop for that error to be supressed and instead the loop to be brought up to ask the user for another input incase the user messed the spelling or case. Could you please elaborate on how to use the exist function. I think it would come in handy.

[Walter Roberson]

myFilename = '';
while ~exist(myFilename, 'file')
   myFilename = input('Please enter the correct data file name(Case sensitive). Ensure spelling is correct:', 's');
end

[Pallav Patel]

clc
clear
close all

%Input for data file name
myFilename = input('Please enter data file name:');
myFilename = '';
while ~exist(myFilename, 'MP_JIT_data.xlsx')
   myFilename = input('Please enter the correct data file name(Case sensitive). Ensure spelling is correct:', 's');
end

%Import data from excel file
[times,Company_name,AllData] = xlsread(myFilename)

I am trying it but I keep on getting an error. Is there anything I am doing wrong. I modified some elements as replacing it directly didn't work

[Walter Roberson]

In the syntax

while ~exist(myFilename, 'file')

the 'file' part is the literal keyword 'file' and is not to be replaced with a file name.

    myFilename = input('Please enter data file name:', 's');
    while ~exist(myFilename, 'file')
      myFilename = input('Please enter the correct data file name (Case sensitive). Ensure spelling is correct:', 's');
    end

[Pallav Patel]

Wow thank you. That works perfectly. Is file a function?

[Walter Roberson]

No, 'file' is an option name

https://www.mathworks.com/help/matlab/ref/exist.html

See also https://www.mathworks.com/help/matlab/ref/isfile.html from R2017b onward.