my @data = split /\n/, <<EOS;
1.57163 ,17:29:57 Simple Dealin
1.57163 ,17:29:57
1.57163 ,17:29:57
1.57163 ,17:29:57
1.57163 ,17:29:57
1.57163 ,17:29:57
1.57163 ,17:29:57
1.571 ,17:
1.57172 ,17:30:08
1.57176 ,17:30:10
EOS

for ( @data ) {
    if ( my ( $quote, $time, $comment ) =
         m{
              ^                # start of string
              (\d\.\d{5})      # a digit, dot and 5 more digits
              \s,              # a space and a comma
              (\d\d:\d\d:\d\d) # an 8 character time
              \s*              # some spaces
              (.*)             # everything else's a commment
              $                # end of string
      }x ) {
        print "$quote / $time",
          $comment ne '' ? " / $comment" : '',
            "\n";
    }
}