Could someone help me understand the input() function?

So what it comes down to is that int(), float(), and input() (as well as print()) are functions that you are calling. In the case of int() and float(), they return (simply put, when you make a function call it "becomes" the return value) an int or float type object based on the argument (the value between the parentheses) that you passed in. In the case of print(), it causes the program to print out the provided argument.

input() is a little more complicated. It prints out the provided argument (in your case: Who are you? ) and then puts the program on pause while it waits for the user to input some text and press enter. Once they have done so, the input function returns the text the user has entered. So as mentioned before, the code input('Who are you? ') "becomes" the text the user input, which then gets assigned to the variable nam.

I think where you may be getting confused is what exactly defines "text". The only things that python considers text (referred to as a string) are characters surrounded by "" or ''. In your example, input('Who are you? ') is not a string, but code to be executed (although the argument being passed to input, 'Who are you? ', is a string). As an experiment, try surrounding that code with quotation marks (name = "input('Who are you? ')") and see what happens!

I think you’ve already gotten some good answers here regarding the function itself:

It sits and waits for the user to input something and hit Enter, and returns the value the user entered, which is then assigned to your nam variable. (See the documentation for the function.

I might also offer the advice of confirming your understanding of the flow of a program. That is, understand that, in the general sense, the computer must resolve the right-hand side of the equals sign to a value before it can assign it to the left.

For example, if the right-hand side is a literal value, it’s already resolved. For example, a line like name = “Joe” is easy—assign the string literal “Joe” to the variable name, when the line is run.

If the right hand side is a mathematical equation, it must be resolved to a value when the line is run. For example, for a line like value = 2+2, the 2+2 must be resolved to 4 before it can be assigned to the variable.

Then, for something like name = input(“Who are you?”), in order to resolve the right-hand side, the computer must first run the function before it can assign a value to the variable name.

It can, of course, get more complicated, where you can call multiple functions on a line, and the results of one feed into the next, and so on. But, that can be an exercise for the near future.

You’re setting ‘nam’ to whatever the output of the function called ‘input’ is. The string asking who are you is an argument to the ‘input’ function. What that function does happens to be that it prints its argument out to the console, waits for the user to enter text, and returns whatever text was entered as its output. I would recommend actually trying out the code and playing around with it if you want to understand it better.

The other two functions you mentioned work similarly. The output of the function named ‘int’ is a new integer. Usually you will give it a number as an argument to set the value of that integer.

Perhaps an example with another function helps, but I will use a list of numbers (lists' syntax uses square brackets).

values = [1, 2, 3]
total = sum(values)

I'm not sure if I'm the best at explaining this, as I'm more fluent in C++, but effectively what is happening is you're providing a prompt for the user's input. The user's input is then assigned to the variable.

In a lot of languages, this would be two lines of code and look something like this:

Output:"Please enter your name"

Name=input

Python is trying to simplify this process

A lot of responses here so I'll suggest a different approach. You can watch your python code execute line by line using a debugger. That might help with understanding how it all works.

def my_sum(list):
    result = 0
    for number in list:
        result += number
    return result

my_list = [1, 2, 3, 4, 5]
list_sum = my_sum(my_list)
print(list_sum)  # Prints 15

If you run the above code line by line in a debugger, you'll see that when it gets to list_sum = my_sum(my_list) the program will jump into the function my_sum(list) where "list" is a variable holding the value of "my_list". The program continues line by line inside of the function until it hits the return result statement. The program then returns to the line it was at before jumping into the function. "my_sum(my_list)" now has an actual value. It's the value that the return statement provided. The line would now read list_sum = 15 to python.

A debugger shows you which lines get executed in which order and how the variables update and change with each line.

Just a note: python has a built-in sum() function you could use instead of writing your own my_sum() function, but a debugger won't show you how built-in functions work! They're built into the language itself. You'd need to look up Python's documentation to see how they actually function under the hood.

@EveryMuffinIsNowEncrypted i maybe wrong

input() is a python function that accepts arguments and returns value of type string.

int() and float() are special type of functions called constructor, magical.

int, or integer, on itself is a datatype like str, or string, is a datatype, to create an int you'd use its costructor int('23') something like that

int is a builtin datatype, so by typing 23, you already have an instance of int

Many people have given you answers of varying lengfhs, so I feel free to ask my counter-question...

You say you had int() and float() but would do you assume would happen if you had just replaced 'input(Who are you?)' with 'int(7)'? What value would be assigned to name if the statement was 'nam = int(7)'?

Following the logic you're espousing in the OP, 'nam' would be equal to the string "int(7)" and the print statement would output "Welcome int(7)". Either you understand why that wouldn't be the case and should see why your original example works. Or you don't and you should double check your understanding of functions and keep tapping people here for help.

I think you need to look into string concatenation, the easiest and best of which is f strings. You could do something like;

print(f'welcome, {nam}')

You could also "add" the strings together.

print('welcome, ' + nam)

Another thing, when assigning the output of something to a variable, you can think of it as "the result of the code right of the equals sign is the value of the variable".

The input function assumes that the value should be interpreted as a string, but what if want it to be a number? You can just wrap another function around your input

user_number = int(input('what's the number?'))

nam is assigned the value returned by input.

This is not some edge case behavior by the input function. This is always how function calls work. You can think of it like substituting input('Who are you? ') with the value returned by it, which is the string typed in by the user in this case.

You got a club? Maybe a nine iron? How about some mayo and a few lacrosse balls?

I will definitely make you understand that input variable.