It is difficult to understand what "for each .." means in your question. If you just need to extract the numbers that you specified, the following is one possible approach:
content = fileread( 'trial.txt' ) ;
matches = regexp( content, '[-\d\.]+(?=-\d)', 'match' ) ;
data = str2double( matches ) ;
which outputs
>> data
data =
87.5000 85.0000 82.5000 80.0000
It may not be the most efficient in term of speed, but it is very concise.. could even be a one liner:
data = str2double( regexp( fileread('trial.txt'), '[-\d\.]+(?=-\d)', 'match' )) ;
