how to ask for both an integer and an string

Question

print("welcome to the Pythagoras calculator")
print("please leave empty whenever asked for any sides of the triangle you do not have data for")
print("please answer every question with integers only")

side = input("which side would you like to be found?")

hyp = int(input("hypotenuse length:"))
if hyp == (''):
    hyp = str(hyp)
adj = int(input("adjacent length:"))
if adj ==(''):
    adj = str(adj)
opp = int(input("opposite length:"))
if opp == (''):
    opp = str(opp)

while hyp == ("") and adj == (""):
    print("you need to insert two values")
    hyp = int(input("hypotenuse length:"))
    adj = int(input("adjacent length:"))
    opp = int(input("opposite length:"))

while hyp == ("") and opp == (""):
             print("you need to insert two values")
             hyp = int(input("hypotenuse length:"))
             adj = int(input("adjacent length:"))
             opp = int(input("opposite length:"))

while adj == ("") and opp == (""):
             print("you need to insert two values")
             hyp = int(input("hypotenuse length:"))
             adj = int(input("adjacent length:"))
             opp = int(input("opposite length:"))

while adj == ("") and opp == (""):
             print("you need to insert two values")
             hyp = int(input("hypotenuse length:"))
             adj = int(input("adjacent length:"))
             opp = int(input("opposite length:"))

while hyp == ("") and adj == ("") and opp == (""):
             print("you need to insert two values")
             hyp = int(input("hypotenuse length:"))
             adj = int(input("adjacent length:"))
             opp = int(input("opposite length:"))

I'm trying to create a Pythagoras calculator yet when I ask people to insert the length of the sides it pops up an error which says that basically I'm trying to use an int as a string ( in validation), I'm aware that I can´t use an int as a string I just can´t figure out how to operate with both string and integers in the same input ( I ask for an input and it is both a string and an integer).

Thanks

`if hyp == ('')` will never happen, if the string is empty you will get an error, if you want to validate input use a try/except. http://stackoverflow.com/questions/23294658/asking-the-user-for-input-until-they-give-a-valid-response — Padraic Cunningham, Jan 06 '16 at 19:13
Write your own input function that checks the length of the string the user enters and uses a try/except clause to see if it can be converted to an integer with `int()` — and then use it everywhere in place of of the `int(input("name:"))`. — martineau, Jan 06 '16 at 19:17

wolfsgang · Accepted Answer · 2016-01-06T19:57:28.173

0

In python 2.7 , you simply use raw_input() like

hyp = raw_input("hypotenuse length:")
adj = raw_input("adjacent length:")
opp = raw_input("opposite length:")

And then your checks will work as they will be empty strings if nothing is entered.

Also you should preferably use raw_input for all inputs, wherever you would need the value as int you explicitly covert it then, like

temp = int(adj)

raw_input() returns a string, and input() tries to run the input as a Python expression.

In python 3, raw_input is just renamed as input and hence can be use directly to get input as string.

edited Jan 06 '16 at 19:57

answered Jan 06 '16 at 19:36

wolfsgang

884
6
12

I hope its clear that the need to convert them to strings will not be needed with those redundant checks. Thus your program will straight away go to the check in those while loops. – wolfsgang Jan 06 '16 at 19:46

score 0 · Answer 2 · answered Jan 06 '16 at 20:17

You could use a try/except block as shown, and add additional conditions to validate for (I checked for number of blank sides in validate_input(), but you could extend to positive numbers, etc).

#!/usr/bin/python

import math

#Triangle has three sides; two can be defined and the third is calculated
class Triangle:

    def __init__(self):
        self.side={"adjacent":0,"opposite":0,"hypotenuse":0}

    def define_sides(self):
        for i in self.side:
            self.side[i]=self.get_side(i)

    def print_sides(self):
        for i in self.side:
            print "side",i,"equals",self.side[i]

    #return user integer or None if they enter nothing
    def get_side(self,one_side):
        prompt = "Enter length of "+one_side+": "
        try:
            return input(prompt)
        except SyntaxError:
            return None

    def count_nones(self):
        nones=0
        for side, length in self.side.iteritems():
            if self.side[side] == None:
                nones+=1
        return nones

    def validate_input(self):
        nNones=self.count_nones()

        if nNones < 1:
            print "You must leave one side blank."
            quit()
        if nNones > 1:
            print "Only one side can be left blank."

    def calculate_missing_length(self):
        h=self.side["hypotenuse"]
        a=self.side["adjacent"]
        o=self.side["opposite"]

        #hypotenuse is missing
        if h == None:
            self.side["hypotenuse"] = math.sqrt(a*a+o*o)

        #adjacent is missing
        if a == None:
            self.side["adjacent"] = math.sqrt(h*h-o*o)

        #opposite is missing
        if o == None:
            self.side["opposite"] = math.sqrt(h*h-a*a)

#begin program
triangle=Triangle()
triangle.define_sides()
triangle.print_sides()
triangle.validate_input()
triangle.calculate_missing_length()
triangle.print_sides()

how to ask for both an integer and an string

2 Answers2