CODEWITHSUNDEEP
matlab
Frederick
Frederick

Reputation: 1301

Convert struct fields from string to number

I have a struct with several fields, some that should be numeric, and some that should be char. However, after my use of regexp I have chars in the fields that I want to use as numbers.

For example:

foo.str = 'one';
foo.data = '1';
foo(2).str = 'two';
foo(2).data = '2';

In my dreams I could do: foo.data = str2double(foo.data), but this does not work.

I could iterate through the struct, but that's only an ok option. It's a long struct (100,000) with about 20 files. 

for i = 1:length(foo)
    foo(i).data = str2double(foo(i).data);
end

Any ideas?

Upvotes: 4

Views: 2157

Answers (3)

chappjc
chappjc

Reputation: 30589

Here is a fairly compact solution that deals numerical values back into each foo.data:

fdnc = num2cell(str2double({foo.data}));
[foo.data] = deal(fdnc{:});

Remember to clear and redefine foo when testing.

EDIT: Fixed vertcat problem with multiple digits. Thanks, nispio.

Upvotes: 2

Luis Mendo
Luis Mendo

Reputation: 112749

A little cumbersome, but this works; no loops:

N = length(foo);
[aux_str{1:N}] = deal(foo.str);
[aux_data{1:N}] = deal(foo.data);
aux_data = mat2cell(str2double(aux_data),1,ones(1,N));
foo = cell2struct([aux_str; aux_data],{'str','data'},1);

Upvotes: 1

Oleg
Oleg

Reputation: 10676

Collect all elements from the subfield and call str2double once:

str2double({foo.data})

Upvotes: 3

Related Questions