All language subtitles for 1. User Input

As you know from the previous lectures we have defined this function.
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And here we are calling it.
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So it checks if the given temperature is greater than seven and it returns a warm
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if that is true, and cold if the temperature is equal to seven or less than seven that's fine.
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But what is the use of this function in a real life setting?
Like who is giving this input?
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You as a programmer you are writing this function for someone else so that they can use it but you don't
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expect them to edit the Python file like to have an editor like Visual Studio Code or other editors,
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and then you cannot just tell them to go to the line 7 and change the values and then execute that code
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to get different outputs depending on the value.
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So how about prompting the user to enter a value, and then the user types in the value and then we get that
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value and process it in our function.
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In that case we get that value and put it in here in the function call.
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Let's do that.
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So we've got a function there. We want to get a value from the user. To get a value from the user
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use the input function, the input function gets an argument and that is the message you want to show
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to the user on the command line.
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For example enter "Enter temperature".
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maybe put a colon there if you like, you can write whatever you like.
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Let me save this script and execute it.
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You see now I executed it and this input function what it does is it freezes the execution of a program
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and waits for user input on the command line.
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So if I put inputs something here like seven in this case what is going to happen is that this expression
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here will be equal to seven.
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However because we didn't do anything here nothing will happen.
If we print out this value
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for example 7 you'll get printed out the value of this which is 7.
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So there you can put anything you want.
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Hi there.
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And you get "Hi there" printed out. What I would suggest is instead of printing this out you'd first
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want to put it in a variable, that would make it more readable so user input, and than you can do whatever
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you want with that variable like lower it, so to print out the lowercase version of that.
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Hi hi. So you get hi hi with lowercase letters, okay.
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Back to our function.
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Let me now try to print out the weather condition function output with a value of, well user inputs, whatever
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the user enters there as inputs, so I'll execute the program now.
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The program will ask me with enter temperature.
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The program will ask me to enter a temperature so the execution is frozen at this point.
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This line has not been executed yet.
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It will be executed after we give a value here and press enter.
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So let me write down six.
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Let's see what we are going to get
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this time, we get an error.
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Let's read the error carefully.
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It's about file basics.py which is our file, okay.
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The error happened at first
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at this line here.
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So you print weather condition user input. When Python tried to execute this line it couldn't do it and
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why?
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Well you have to follow the error.
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So still line basics.py line 2, at this line.
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So when Python tried to execute this line, that line called some other things in the script and the
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error was in this line.
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Line 2.
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So when the function call tried to call the function, it tried to execute this line.
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So if temperature... It tried to compare 5 with 7, and then it got this error when it's tried to compare
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5 with 7.
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So when it's tried to execute this line in other words.
See what it says.
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Type error.
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This operator is not supported between instances of string and integer, so string and int.
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Which means this was a string and this was an int.
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So our user input was 7, was passed in here and that was compared with 7.
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It seems that our input the user input was a string and that is true.
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That was the point I was trying to make here because whatever input the user writes in here even if
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it's a number.
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Python will actually converted to a string.
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So 7 in fact will be converted to a string like with quotes or double quotes inside Python but that
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has an easy fix.
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What you can do is you can convert this value which is the string 7,
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you can convert it into a float.
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Be careful with the parentheses, so float is a function.
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It has an open parentheses in here and it has a closing parentheses in here.
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Input is also a function with its own opening and closing parentheses, so no if I do that, enter temperature 5,
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I'm going to get the correct answer and let me be transparent with you.
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Let's again input gets user input "Enter some input".
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Let me now
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print out that type of user input, execute, enter 6, you'll see that 6 actually is a string.
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That's why I am converting it into a float, so that 6 this time will be a float actually which looks like
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this.
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You can print out the actual number here, the actual convert number, the float version of the number.
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Execute again.
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6, so 6.0.
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You can also use int if you like.
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6 so you'll get six which is equal to six point zero of course, but floats would be a better choice because
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I can show you why, if you enter 6.3 for example int will not be able to convert it because
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that is like doing int 6.3 in double quotes so int will get confused you will not know how
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to convert that into an integer.
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It does however convert 6
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if it was a simple six without a decimal point. Float will convert both.
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Sorry both 6 and 6.3.
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And that's how you use user input in Python.