How do I loop this

Question

Pretty new to Python and am using 2.7 to script.

a = raw_input("Input number or decimal only")
Try:
    Y = float(a)
    print a
except ValueError:
    print "wrong input, try again"

I need to loop this - if the input is either alphanumeric or letters, it should ask for input again.

I can't seem to find a way to slide in a while loop in it.

(Python newbie, please be kind!)

Did you copy paste your code or re-type it? Because as is this code won't run. — idjaw, Oct 17 '15 at 18:21

Flying_Banana · Answer 1 · 2015-10-17T18:35:12.540

0

correct = False
a = ""
while not correct:
    a = raw_input("Input number or decimal only")
    correct = a.isalnum()
    if not correct:
        print "wrong input, try again"
print a

edited Oct 17 '15 at 18:35

answered Oct 17 '15 at 18:25

Flying_Banana

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I'm showing OP where to insert the loop only :) – Flying_Banana Oct 17 '15 at 18:27
1

That will never break from loop, what is the point of this? – Tim Oct 17 '15 at 18:28
Didn't read the problem close enough. Edited. – Flying_Banana Oct 17 '15 at 18:32
Bit better. Still not sure why use try / except. You also have no need to declare a="" and correct being used like that seems silly. Just make the loop depend on it? – Tim Oct 17 '15 at 18:35
@Tim I am going to give a +1 for readability. it reads very nicely. – Joseph Farah Oct 17 '15 at 19:24

score 0 · Answer 2 · answered Oct 17 '15 at 18:29

0

input = "%"    # Set to be non alphanumeric so loop starts
while not input.isalnum():
    input = raw_input("Input number or decimal only > ")
    if not input.isalnum():
        print ("Invalid Input, try again")
    else:
        print (input)

answered Oct 17 '15 at 18:29

Tim

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score 0 · Answer 3 · answered Oct 17 '15 at 22:16

0

while True: # Loops!
    a = raw_input("Input number or decimal only\n")
    try:
        Y = float(a)
        print a
        break # Interrupts the loop if the input was a number
    except ValueError:
        print "wrong input, try again"

'while True' loops forever, the only way to stop it is 'break' within the loop

answered Oct 17 '15 at 22:16

Aah, thank you! I figured it would something easy. Appreciate the help :) – Doran Oct 18 '15 at 16:38
No problem! Ask if you need anything else – Oct 18 '15 at 17:10

How do I loop this

3 Answers3