Python call a function using a string from users input

Question

In this program I am using a a user input to select which alignment the user wnats to align some text, at present I'm usinf if statements like so...

if alignment == "Left":
 line = left(new_string)
elif alignment == "Right":
 line = right(new_string)
elif alignment == "Centre":
 line = centre(new_string)
elif alignment == "Fully":
 line = fully(new_string)
else:
 print "Error."

However, is there a a way that i can get rid of these statements and just use the users input to call either the left, right, centre, fully functions.

Thanks JT

Answer 1

Map the alignment string to functions with a dictionary:

alignments = {'Left': left, 'Right': right, 'Centre', centre, 'Fully': fully}
try:
 line = alignments[alignment](new_string)
except KeyError:
 print "Error."

Python functions are first-class objects, so you can just store them as values in a dictionary.

Answer 2

func = globals().get(alignment.lower())
if not func:
 func = locals().get(alignment.lower())
func(new_string)

You should make sure that func is not None at the time it is called.

Answer 3

Evaluate it

try:
 eval(alignment.lower())(new_string)
except NameError:
 print 'Error'

• glglgl: Yeehaw! Let's input os.system then... and as new_string... let's take something arbitrary, such as rm -rf /, maybe...