extracting numeric vulues from cell char

hello every one; who can help me how to extract these email addresses from numeric values which placed before @ character:

km={'[e-mail]';'[e-mail]';'[e-mail]';'[e-mail]';'[e-mail]';'[e-mail]';'[e-mail]';'[e-mail]';'[e-mail]';'[e-mail]';'[e-mail]';'[e-mail]'}
thanks in advance.

Answer 1

[Guillaume]

Regular expressions are very good for this:

km = {'[e-mail]'
      '[e-mail]'
      '[e-mail]'
      '[e-mail]'
      '[e-mail]'
      '[e-mail]'
      '[e-mail]'
      '[e-mail]'
      '[e-mail]'
      '[e-mail]'
      '[e-mail]'
      '[e-mail]'};
numasstring = regexp(km, '\d+(?=@)', 'match', 'once') %find sequence of digits immediately followed by @.
numbers = cellfun(@str2double, numasstring)