CODEWITHSUNDEEP
pythonnumbers
Brandon Smith
Brandon Smith

Reputation: 3

Why does this print if it's above value 99?

mySpeed = input("What is your speed? ")

if mySpeed < ("50"):

    print ("safe")

Why does this print if the value is above 99?

Upvotes: 0

Views: 183

Answers (5)

Ryan
Ryan

Reputation: 81

You can't evaluate a string as if it were an integer. Think of a string as the word "ten", whereas the integer is "10". You can't add the three letters t-e-n to an integer and result in a number. However, you can add "10+10", for example to result in "20". Your code should look like this:

mySpeed = int(input("What is your speed? "))

if mySpeed < 50:
      print ("safe")

NOTE: by using the int() function to turn users' input into an integer, you are not in fact verifying what they input. If the user inputs a string, such as "ten", your code will return an error because "ten" cannot be converted into an integer.

My answer isn't best practice, but it will "work".

Upvotes: 0

KillianDS
KillianDS

Reputation: 17186

Because you are comparing two strings, not two integers. A string is a sequence and for a sequence comparison works as follows:

The comparison uses lexicographical ordering: first the first two items are compared, and if they differ this determines the outcome of the comparison; if they are equal, the next two items are compared, and so on, until either sequence is exhausted.

So if you take a number large than '99', e.g. '100' it will take the first character '1' and compare it to '5' (first character of '50'). '1' is smaller than '5' in ascii ('1'==49 and '5'==53). So this comparison will already terminate and the result will be that indeed '100' is smaller than '50'.

For the same reason '9' is not smaller than '50':

In [1]: b'9'<b'50'
Out[1]: False

You should compare integers, as follows:

mySpeed = int(input("What is your speed? "))
if mySpeed < 50:    
    print ("safe")

Upvotes: 2

&#211;scar L&#243;pez
&#211;scar L&#243;pez

Reputation: 236094

Try this:

mySpeed = int(input("What is your speed? "))
if mySpeed < 50:
    # same as before

Explanation: you should read a number and compare it against a number. Your code currently is reading a string and comparing it against another string, that's not going to give the results you expect.

Upvotes: 4

MrAlexBailey
MrAlexBailey

Reputation: 5289

mySpeed < ("50") is checking a string. You need to be working with integers:

mySpeed = input("What is your speed? ")

if mySpeed < (50):
    print ("safe")

Upvotes: 0

cleros
cleros

Reputation: 4343

"50" is a string, not a number ... try eliminating the " " ...

If mystring is a string, try a cast with the int-function - e.g. int(mystring)

Upvotes: 1

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