Extracting a number from a sentence string

I am trying to extract numbers from a sentence string through a function that does not know the exact placement or how many numbers are in the string.

for example my input would be

a='my weight is between 200 and 250 lbs'

or it could be

a='my weight is 200 lbs'

the weight will always be before "lbs", but the length of weight string is unknown.

I am having trouble using the sscanf function to make a universal code to extract the numbers from a string. Any help is greatly appreciated.

Answer 1

[per isakson]

A start

    >> a='my weight is between 200 and 250 lbs'
    a =
    my weight is between 200 and 250 lbs
    >> cac = regexp( a, '\d++', 'match' )
    cac = 
        '200'    '250'

Warning: This will not match '1.2E-003', not even '-4' :-(