All language subtitles for 2. String Formatting

How would you make a program that behaves like this?
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It asks you for your name and you put your name as a user, and the program will greet you, wLL output
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a message "Hello" and your name there, and also an exclamation mark at the end of the string.
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Well you do that with two things.
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First you need the input function to ask the user for input,
to prompt the user for input and then you
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need string formatting.
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This is how string formatting looks like in Python.
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So in the first line, we are getting the user input, storing that input as a string in user input.
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Then we create a variable. In that variable, we will store the message we are constructing and this here
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is a string formatting expression.
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So we want to print out "Hello", and then have a space and then we want to print out the name of the user.
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So the value that the user inputs. This here, %s is a special string in Python, then we have
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an exclamation mark which is a normal string and the double quotes.
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So this is special here.
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And then after the string, you don't want to put a comma.
What you want to do is use this percentage
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operator and then use a variable.
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Now the value of this variable will go and replace the %s.
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So what you get instead is "Hello"
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and your name there.
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Now, this method of string formatting by using this %s here and percentage operator in here,
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this is valid for Python 2 and Python 3 as well.
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Now there is another method that was introduced in Python 3.6.
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So the method I'll introduce now will not work if you run it with a Python version earlier than
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3.6.
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The method goes like this.
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Let's store the entire string in a variable again and so it will be a string with double quotes or single
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quotes whatever you prefer.
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I'm using double quotes, so "Hello", and you use these curly brackets and inside that you put the name
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of the variable which value you want to be put in this place.
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Now this is not all.
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So if I save these and execute the code and I say "Ardit", it will return the string.
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So we need to do something else.
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What we need to do is we need to add a prefix f just outside of the qoutes.
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So this is the string.
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This f goes outside of the quotes.
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If I save the script now, execute again, write my name, and now we get the expected output, note that
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we've got two variables with the same name here.
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And what it will happen is that the first Python executes a script from top to bottom so it executed
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the first line it executes the second line.
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So it will store "Hello Ardit" in the message variable, but then we are overwriting that variable.
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So in this case the string will be written in that message variable.
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So whatever you create in here, whatever object you store in here, in the variable that object will be
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the current object that that variable will refer to.
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So in this case here you will print out the object that you created in here which happens to be "Hello Ardit".
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Which one should you use?
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Well, if you think that your project is going to be run with Python 3.6 or above, then use this
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nicer version, it's more readable, if you think that your project, your python files will be run with
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Python 2 or 3.1, or 3.2, or 3.3, then you might want to opt in for this method because sometimes
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when you deploy your scripts in a server for example let's say you want to execute a script every day
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at the certain hour, you want to deploy it on a web server, and that's web server will have a specific
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version of Python.
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Sometimes that version is Python 2.
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So in that case you want to adjust your scripts so that it works with Python 2 and the web server,
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the server, the computer will run your script with a particular Python version.
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We're going to look at this later when we deploy the web apps.
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So for now these are the two methods of string formatting.