Python- While Loop with error handling

Question

Ive been reading up on while Loops while learning python. The following works without error, however if I insert 16 as value, I get

Insert numbers only
Your weight is 16 lbs

This is not correct

while True:
    weight_input = raw_input ("Add your weight: ")+(" lbs")
    try:
       val = int(weight_input)
    except ValueError:
        print("Insert numbers only")

    print("Your weight is " + weight_input + "!")

What am I missing ? I am trying to print out weight and if value = anything other then a integer then send error.

UPDATE

Decided on using tables with above . I get a error adding "lbs" Any help? print(tabulate([[weight_input]+"lbs"], tablefmt='pipe', headers=('Weight')))

The value of weight_input is "16 lbs". That's not a valid integer — Patrick Haugh
– Patrick Haugh, Commented Jan 22, 2018 at 20:13

Alex · Accepted Answer · 2018-01-22 20:13:13Z

5

You are adding " lbs" to the input which makes the variable weight_input "16 lbs". You can add the "lbs" to the message that you display at the end of the loop:

while True:
    weight_input = raw_input ("Add your weight: ")
    try:
       val = int(weight_input)
    except ValueError:
        print("Insert numbers only")

    print("Your weight is " + weight_input + " lbs!")

answered Jan 22, 2018 at 20:13

Alex

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3 Comments

Benjamin Jones Over a year ago

Thanks that worked! Sorry for dumb question. How do I end the loop?

Alex Over a year ago

You can use the keyword break. See the docs on control flow.

Benjamin Jones Over a year ago

I did the following above. Decided on using tables . I get a error adding "lbs" Any help? print(tabulate([[weight_input]+"lbs"], tablefmt='pipe', headers=('Weight')))

Pedro von Hertwig Batista · Accepted Answer · 2018-01-22 20:12:54Z

3

When you do

weight_input = raw_input ("Add your weight: ")+(" lbs")

You're adding the +(" lbs") to your input string. Try removing that.

answered Jan 22, 2018 at 20:12

Pedro von Hertwig Batista

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1 Comment

wwii Over a year ago

Try removing that - Is this an answer that you know works or are you guessing? Maybe you should format this as an answer instead of a suggestion.

Sphinx · Accepted Answer · 2018-01-22 20:29:33Z

1

You have to remove the trailer=(" lbs") of raw_input first, then check if the input is one number by .isdigit().

while True:
  weight_input = raw_input ("Add your weight (type 'end' to exit'): ")
  if weight_input === 'end':
    break #use 'break' to quit the loop
  if not weight_input.isdigit():
    print("Insert numbers only")
  else:
    print("Your weight is " + weight_input + " lb!")

edited Jan 22, 2018 at 20:29

answered Jan 22, 2018 at 20:22

Sphinx

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1 Comment

Alex Over a year ago

While this is valid, Pythonistas tend to prefer the EAFP approach.

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