Python Making Input Statements

[Jason]

Making input statements is vitally important because, of course, we might someone on the outside to give information, you know, like in a survey or whatever. Anyway, input statements aren't much in Python and probably not much in other languages either.

Getting Our Feet Wet

Let's dive into this topic with some examples. Notice that aside from strings, you need to declare the datatype so things don't mess up. I was wondering, though, as I'm not an expert, only a learner, can you also declare the str type?

your_gpa = float(input("What is your gpa?"))

print("Your gpa was recorded as" + " " + str(your_gpa) + ".")

your_age = int(input("What is your age?"))

print("Your age is recorded as" + " " + str(your_age) + ".")

your_school = input("What is your school?")

# Notice we didn't have to declare the str type.

print("Your school is recorded as" + " " +  (your_school)  + ".")

do_you_play_sports = bool(input("Do you play sports, true or false?"))

print("It is recorded that it is" + " " + str(do_you_play_sports) + " " + "that you play sports." + ".")

This is quite straightforward. Any questions? Have you run into Python applications where this stuff was probably used? How did it go?

 

[Arantor]

OK, so there's a few things I need to clarify here.

Everything in Python has a type, by definition, by design. Nothing exists in a typeless form - it literally can't. Things like bool(), int() and so on aren't 'declaring the type', they're *changing* it.

int('5') is 'take a string that is the character 5 and turn it into a whole number'
int('500') is 'take a string of 3 characters, a 5, a 0 and a 0 and turn it into a whole number'

input() as a function *always* returns a string - this is why you 'didn't need to declare it as a str' because it already is one. You do, however, need to do it for some of the other things - because you can't just 'add a number to a string' or somesuch. ("adding two strings" is really the process of sticking one on the end of the other, better known as concatenation, and is why you have to have str() around things that aren't strings to join them together)

One final note, bool(input(...)) doesn't do what you think it will do. Coercing to bool means 'is the value of the thing truthy or falsy' and reducing it down to True or False. Truthy values are numbers that aren't zero, values that aren't None, or lists/sets/dicts that aren't empty. Crucially in this case, a truthy string is one that contains content. So if you ask for 'true or false' in input() and get in 'false', bool('false') will return True because it *doesn't look at the value in that case*. It simply asks 'is this an empty string, yes/no, not empty therefore True'

 

[Jason]

Some corrections and editing with the spacing stuff. How is it running now?

 

[Arantor]

You could try running it yourself. You might find that the sports question will always say True unless you enter literally nothing.

 

[Jason]

You could try running it yourself. You might find that the sports question will always say True unless you enter literally nothing.

I don't have any complier. I gotta get my own computer. Well, maybe I could get it on this library computer. I don't know.