Common substring index from two string arrays

I have two string arrays a and b and I need to find the index matching the substring numbers (within string arrays). For example, in a string array a, 01, 02, 03 are the substrings matching in string array b.

a = {'frame01', 'frame02', 'frame03'};
a = string(a);

b = {'capture00.jpg' 'capture01.jpg', 'capture02.jpg', 'capture03.jpg', 'capture04.jpg'};
b = string(b)

Desired output index of string array b should be:

Index_b = [2 3 4]

Desired output index of string array a should be:

Index_a = [1 2 3]

Without for-loop solution is preferred.

Any help is appreciated!

[Stephen23]

The substrings 'a', 'e', and 'r' are also substrings common to both arrays: why are you not listing them?

[Preetham Manjunatha]

Yes, you are right. Sorry I did not include it has to be substring numbers. I edited that in the question. Thanks for pointing it out!

[Stephen23]

Do the substring numbers require the same leading zeros or just the same numeric value, i.e. is '3' the same as '03' ?

[Preetham Manjunatha]

It is numbers with leading zeros in this example. But in general can be without leading zeros.

Answer 1

[Stephen23]

a = ["frame01", "frame02", "frame03"];
b = ["capture00.jpg", "capture01.jpg", "capture02.jpg", "capture03.jpg", "capture04.jpg"];
[~,ia,ib] = intersect(regexp(a,'\d+','once','match'),regexp(b,'\d+','once','match'))

ia = 3×1

1 2 3

ib = 3×1

2 3 4

[Preetham Manjunatha]

Thanks!

[Stephen23]

And if you want to compare numeric values (i.e. disregard the leading zeros) then:

a = ["frame01", "frame02", "frame03"];
b = ["capture00.jpg", "capture01.jpg", "capture02.jpg", "capture03.jpg", "capture04.jpg"];
[~,ia,ib] = intersect(...
    str2double(regexp(a,'\d+','once','match')),...
    str2double(regexp(b,'\d+','once','match')))

ia = 3×1

1 2 3

ib = 3×1

2 3 4