CODEWITHSUNDEEP
matlabvariablesscopemachine-learningmatlab-figure
user3778989
user3778989

Reputation: 127

Error in matlab code for declaring a variable and then using it

Declaring a variable (filename) in line 2 and using it in line 4 gives error. If I give use data.temp(12,;) then it runs fine but if i give filename = temp and index = 12 as an input and then run data.filename(index,:); ,it gives an error. Somebody please help me out here
Here is the exact code:

data = importdata('check.mat');
filename = input('Enter the filename: ','s'); 
index = input('Enter Index of the file: '); 
row = data.filename(index,:);

Reference to non-existent field 'filename'

Upvotes: 1

Views: 45

Answers (2)

TroyHaskin
TroyHaskin

Reputation: 8401

As an alternative to getfield, you can also use dynamic field names that, in the recent versions of Matlab I've used, permit direct indexing of the referenced field:

stuff = data.(filename)(index,:);

The sub-expression data.(filename) resolves to the data in the field filename of the data struct and (index,:) then indexes that data.

Upvotes: 1

Ander Biguri
Ander Biguri

Reputation: 35525

You are using structs wrongly.

When accessing a structure using a string, you need to use getfield, because fieldname contains a string, but when you do data.fieldname you are not actually using the value of fieldname in after the point, but actually triying to access the field fieldname in data, which doesn't exist.

Instead do:

row=getfield(data, filename);

Upvotes: 5

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