trying to recall a regex for re.split()

[Pedroski55]

Ah well, I presumed you would only be receiving frequency data as Hertz from some CIA outpost in Alaska!

Maybe the spooks are also sending recipe data to their mothers. oz, lbs

measurements = ['2.5hz','2.5Hz', '2.5mHz', '2.5GHz', '2.5THz', '2.5mTHz', '2.5', 'h', 'HZ', 'Hz' ]
my_pattern = re.compile("[a-z, A-Z]")
for m in measurements:    
    # if there is no text
    try:
        start_pos = my_pattern.search(m).span()[0]
        print('measured frequency is', m)
        start_pos = my_pattern.search(m).span()[0]
        print('number =', m[:start_pos], 'units =', m[start_pos:])
    except AttributeError:    
        continue