If statements in python. Does not stop the other if statements from working

Question

import turtle

print("Give me a shape")
shape = input()

if shape == "pentagon" or "Pentagon":
    for i in range(5):
        turtle.fd(100)
        turtle.rt(72)

if shape == "triangle" or "Triangle":
    for i in range(3):
        turtle.fd(100)
        turtle.rt(120)

if shape == "square" or "Square":
    for i in range(4):
        turtle.fd(100)
        turtle.rt(90)

if shape == "hexagon" or "Hexagon":
    for i in range(6):
        turtle.fd(100)
        turtle.rt(60)

if shape == "circle" or "Circle":
    turtle.circle(100)

else:
    print("Not a shape")

Related: http://stackoverflow.com/questions/12774279/python-how-to-check-if-a-variable-is-equal-to-one-string-or-another-string — Łukasz Rogalski, Jun 22 '15 at 07:47
Since you're not using the value of `i` in `for i in range(...)`, I'd suggest using `for _ in range(...)`. Using an underscore as the loop variable is a common convention which emphasises that something is being repeated, and that the loop variable isn't important. — alexwlchan, Jun 22 '15 at 12:47

Delimitry · Answer 1 · 2015-06-22T08:41:16.617

Your check shape == "pentagon" or "Pentagon" is incorrect and will always be True, because checking string always return True, e.g. bool("Pentagon") is True and checking of "pentagon" == "pentagon" is True.
You should use shape in ["pentagon", "Pentagon"] or better shape.lower() == "pentagon" instead.

import turtle

print("Give me a shape")
shape = input().lower()  
if shape == "pentagon": 
    for i in range(5): 
        turtle.fd(100) 
        turtle.rt(72)    
elif shape == "triangle": 
    for i in range(3): 
        turtle.fd(100) 
        turtle.rt(120)    
elif shape == "square": 
    for i in range(4): 
        turtle.fd(100) 
        turtle.rt(90)    
elif shape == "hexagon": 
    for i in range(6): 
        turtle.fd(100) 
        turtle.rt(60)    
elif shape == "circle": 
    turtle.circle(100)    
else: 
    print("Not a shape")

Wouldn't `shape = input("Give me a shape: ").lower()` be an improvement rather than changing the case for every condition? — cdarke, Jun 22 '15 at 08:25

score 1 · Answer 2 · answered Jun 22 '15 at 07:50

1

Your statements like

shape == "pentagon" or "Pentagon"

evaluate to True or "Pentagon".

You need to compare shape to both values:

shape == "pentagon" or shape == "Pentagon"

answered Jun 22 '15 at 07:50

tynn

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score 0 · Answer 3 · edited Jun 22 '15 at 12:44

You should use elif statements after the first if. Alternatively you could convert your input to lower case by using '.lower'. Which would mean that you wouldn't have to have an or in the statements. It would also accept TRIANGLE for example.

import turtle

print("Give me a shape")
shape = input()

if shape == "pentagon" or shape == "Pentagon":
    for i in range(5):
        turtle.fd(100)
        turtle.rt(72)

elif shape == "triangle" or shape == "Triangle":
    for i in range(3):
        turtle.fd(100)
        turtle.rt(120)

elif shape == "square" or shape == "Square":
    for i in range(4):
        turtle.fd(100)
        turtle.rt(90)

elif shape == "hexagon" or shape == "Hexagon":
    for i in range(6):
        turtle.fd(100)
        turtle.rt(60)

elif shape == "circle" or shape == "Circle":
    turtle.circle(100)

else:
    print("Not a shape")

When I do that it does the first one and then none of the others. For example if I type circle it will only print out the pentagon and then stop. — Jennifer Taylor, Jun 22 '15 at 07:42
That is beacsue the or "Pentagon" will always be True as you aren't re-evaluating shape. Please see my edit. — Rob, Jun 22 '15 at 07:51

If statements in python. Does not stop the other if statements from working

3 Answers3