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+--- Thread: Single digits seem to be greater than double digits (/thread-31062.html)
Single digits seem to be greater than double digits - Frosty_GM - Nov-20-2020
Hello, I am new to Python and I've been playing around with the 'Hello World' script that everyone probably starts with
I wanted to see if i could you 'if' properly so I made 2 'if' lines that would print a different response depending on 'age=input()'
I created a simple equation to write if the age=input() was <'18'. It simple finds the different between 'age=input()' and '18' to print how long is left until 18.
The trouble is, if 'age=input()' is a single digit int such as 4 or 9, the script will print the line for 'age>='18'. Almost like a single digit int is greater than '18'
Here is the code:
print('hello world!')
print('What is your name?')
name=input()
print('That is a nice name, '+name)
print('How old are you, '+name+' p.s. put a zero infront of a single digit')
age=input()
if age>='18':
print("if you're "+age+", that means it's beer o'clock!")
diff=str(18-(int(age)))
if age<'18':
print('That means you have to wait '+diff+' years to have a drink on me!')
Here is the output if age is a single digit int:
hello world!
What is your name?
G
That is a nice name, G
How old are you, G p.s. put a zero infront of a single digit
2
if you're 2, that means it's beer o'clock!
Whereas is you put a '0' infront of the single digit int, it works:
hello world!
What is your name?
G
That is a nice name, G
How old are you, G p.s. put a zero infront of a single digit
02
That means you have to wait 16 years to have a drink on me!
Any help is appreciated!
RE: Single digits seem to be greater than double digits - sandeep_ganga - Nov-20-2020
See below, i used to typecast to str only at print, rest comparisons in int.
print('hello world!')
print('What is your name?')
name=input()
print('That is a nice name, '+name)
print('How old are you, '+name+' p.s. put a zero infront of a single digit')
age=int(input())
diff=18-age
if age>=18:
print("if you're "+str(age)+", that means it's beer o'clock!")
if age<18:
print('That means you have to wait '+str(diff)+' years to have a drink on me!')Output:C:\Users\sandeep\Downloads>py hh
hello world!
What is your name?
user1
That is a nice name, user1
How old are you, user1 p.s. put a zero infront of a single digit
2
That means you have to wait 16 years to have a drink on me!
C:\Users\sandeep\Downloads>py hh
hello world!
What is your name?
user2
That is a nice name, user2
How old are you, user2 p.s. put a zero infront of a single digit
0
That means you have to wait 18 years to have a drink on me!
C:\Users\sandeep\Downloads>py hh
hello world!
What is your name?
user3
That is a nice name, user3
How old are you, user3 p.s. put a zero infront of a single digit
25
if you're 25, that means it's beer o'clock!Sandeep.
GANGA SANDEEP KUMAR
RE: Single digits seem to be greater than double digits - Frosty_GM - Nov-20-2020
Ahh legend thank you!
I tried playing around with str(int(age)) stuff like that but obviously didnt work.
Thanks for the help
RE: Single digits seem to be greater than double digits - perfringo - Nov-20-2020
Comparing strings doesn't work like comparing numbers.
String comparison is based on character code points and can be desribed as follows:
- comparing the n-th characters of each string (starting with 0-th index) using the == operator
- if they’re equal, repeat this step with the next character
- in case of two unequal characters, string with the character that has the lower code point is 'less' than other
- if all characters are equal, the strings are equal
- if one string is shorter i.e. runs out of characters during comparison (one string is a “prefix” of the other), the shorter string is “less than” the longer one
Codepoints for characters 0..9 are:
>>> [ord(str(i)) for i in range(10)] [48, 49, 50, 51, 52, 53, 54, 55, 56, 57]Therefore:
>>> '18' < '2' # code point of '1' is smaller than of '2' True >>> '18' < '02' # codepoint of '1' is larger than of '0' False
RE: Single digits seem to be greater than double digits - DeaD_EyE - Nov-20-2020
Please use the
[python][/python]tags to wrap your code. Otherwise the indentation is lost and syntax highlighting does not work.
print("hello world!")
print("What is your name?")
name = input()
print("That is a nice name, " + name)
print("How old are you, " + name + " p.s. put a zero infront of a single digit")
age = input()
if age >= "18":
print("if you're " + age + ", that means it's beer o'clock!")
diff = str(18 - (int(age)))
if age < "18":
print("That means you have to wait " + diff + " years to have a drink on me!")In Line 9 you're comparing two strings.The comparison of str is made via lexicographical order.
Here are some hexadecimal values:
Whitespace == 0x20
0 - 9 == 0x30 - 0x39
A - Z == 0x41 - 0x5a
a - z == 0x61 - 0x7a
If you compare this:
"1" > "18"The interpreter compares char by char.
(0x31,) > (0x31, 0x38)But if you compare
"4" > "18", you have this values:(0x34,) > (0x31, 0x38)So, the first one is bigger and this explains why
"4" > "18" == True.If you want to compare numbers, then convert the
str into int.print("hello world!")
print("What is your name?")
name = input()
print("That is a nice name, " + name)
print("How old are you, " + name + " p.s. put a zero infront of a single digit")
age = int(input())
if age >= 18:
print("if you're " + str(age) + ", that means it's beer o'clock!")
diff = 18 - age
if age < 18:
print("That means you have to wait " + str(diff) + " years to have a drink on me!")The concatenation of str should not be done with + operator. If you work with int, float or other types, you've to convert them back to a str. Instead, use string formatting. With modern Python, we have f-strings. A f in front of the " introduces a format-string. The names in the curly braces are replaced with their values. For example, {age} is replaced with the age, which is an int.print("hello world!")
print("What is your name?")
name = input()
print(f"That is a nice name {name}")
print(f"How old are you {name}")
age = int(input())
if age >= 18:
print(f"if you're {age} that means it's beer o'clock!")
diff = 18 - age
if age < 18:
print(f"That means you have to wait {diff} years to have a drink on me!")The benefit is, that you don't have to convert the int explicit back to a str if you're using string formatting.