Python Jumpstart by Building 10 Apps Transcripts
Chapter: App 1: Hello (you Pythonic) world
Lecture: Core concepts: Variables and calling functions

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0:01 The first concept is around this idea of calling functions,
0:04 print is a function, input is a function
0:06 these are usable pieces of functionality in our application.
0:11 Here we are calling a function called main,
0:12 and you can see that you call it with the parenthesis on the end
0:16 some languages have semicolons to indicate the end of a line,
0:20 thankfully, Python does not have that,
0:22 and this takes no arguments and it returns no value
0:25 so you just call like this.
0:27 Now, the input on the other hand,
0:29 we can call it and we pass it a string, kind of like print,
0:32 but then it returns whatever the user inputted.
0:35 So we are to create a variable called saying,
0:38 we are storing the return value from the input function
0:42 which is what you just typed into the saying variable
0:45 we can work with that later.
0:47 So that brings us to variables.
0:49 And variables in Python are very simple,
0:51 they are sort of no-nonsense,
0:53 so you just say the name, or the word you want to use for the variable
0:56 and then you assign to it and- the variable exists.
0:59 Some languages you have to specify types and initialization and so on,
1:03 Python is sort of as simple as it can be around variables.
1:07 So here we have a variable called name,
1:10 and we are assigning it the value Michael,
1:12 we have a variable called age and we are assigning it 42,
1:14 and we can even increment this value of the age,
1:18 we are doing a plus equals operations,
1:20 so we are taking the age, adding 1 to it,
1:22 now the age is 43, so happy birthday to me.
1:25 We have more complex variables of course,
1:27 here we are creating what is called the list
1:29 and we are populating the list with 3 strings,
1:33 so biking, motocross and programming,
1:34 and then we are storing that list holding those objects in the hobbies.
1:38 So, all of these are directly created upon assignment,
1:42 we can also create variables and store return values from functions,
1:45 so here we have home address and we call in a function
1:47 and we are storing the result of that function into home address.
1:50 So let's go back and use these ideas
1:53 to finish up our "Hello World" app.