How to replace string that perfectly matchs the string?

The title might be a litle vague, but I am looking to replace a string on a text by another string using regexprep or any other function. However, all my attempts have failed.

For the following example:

str = 'a = 1; b = 2; var1 = a + b; bar1 = a*b;'

If I use regexprep

>> regexprep(str, 'a', 'v1')

ans =
    'v1 = 1; b = 2; vv1r1 = v1 + b; bv1r1 = v1*b;'

However, I was looking for:

'v1 = 1; b = 2; var1 = v1 + b; bar1 = v1*b;'

I have been reading the documentation and try differents aproachs, but I could not figure out this. I have a feeling that regexprep can easily solve this problem. I just need to trick this a bit.

Tks in advance, I will keep digging on.

Answer 1

[Ameer Hamza]

str = 'a = 1; b = 2; var1 = a + b; bar1 = a*b;';
new_str = regexprep(str, 'a\>', 'v1');

Result:

new_str =
    'v1 = 1; b = 2; var1 = v1 + b; bar1 = v1*b;'

See Anchors: https://www.mathworks.com/help/matlab/ref/regexprep.html#btrbo5i_sep_shared-expression in the documentation.

[Erivelton Gualter]

How I missed that.

Thank you Ameer.

Best,

[Erivelton Gualter]

Hi Ameer,

Actualy it did not work quite well. Check the following example:

str = 'An = B(m+1:n,m+1:n); C = D(1:m,mn+1:n);'

It is returning the following:

regexprep(str, 'n\>', 'X')
ans =
    'AX = B(m+1:X,m+1:X); C = D(1:m,mX+1:X);'

However, the output should be:

ans =
    'An = B(m+1:X,m+1:X); C = D(1:m,mn+1:X);'

[Ameer Hamza]

For this specific case

str = 'An = B(m+1:n,m+1:n); C = D(1:m,mn+1:n);';
new_str = regexprep(str, '([^\w])n\>', '$1X')

Result:

new_str =
    'An = B(m+1:X,m+1:X); C = D(1:m,mn+1:X);'

The actual regular expression depends on the complete specification of the string.