>>> units = {"k":1000,"m":1000000}
>>> num=["11.4k" , "550" , "1.23m" , "30"]
>>> result=[]
>>> for n in num:
... try:
... result.append( float(n) ) #try to comber it to a number
... except ValueError:
... unit=n[-1] #get the letter
... n = float( n[:-1] ) #convert all but the letter
... result.append( n * units[unit] )
>>> result
[11400.0, 550.0, 1230000.0, 30.0]