Delete recurring character from Matrix

    Dec 31 2013 | 4:14 pm
    Hey this might be pretty simple but I can't seem to figure it out, I'm pretty new to this. I have a matrix of data imported from the web that looks something like this (only many times longer):
    773 P
    428 P
    -121 P
    -878 P
    -946 P
    -1220 P
    -1430 P
    -815 P
    2320 P
    7180 P
    9280 P
    10300 P
    10800 P
    11500 P
    I need to remove the 'P' from every line and find the average of the numbers. I can't offset the matrix because the different lengths of the numbers. Any clues?
    Thanks all!