Python for Beginners – Learn Python Programming
Iphone or iPad you need to install a couple of other things first so you go to the App Store and search for Pycharm. Then in the App Store click on the install button. Now. Once Pycharm is installed, you can open it up by clicking on this icon. Here in your downloads folder. You should also have a.py file. So let’s open that up now. The first thing you ‘re going to do is create a new project so let’s do that by clicking on this green plus sign here in your project explorer window and type in Python. This is the name of your project. Now let’s choose a location for your project so we’re going to choose a folder on our computer called projects and then click on the create Button Now let’s change some settings inside of Pycharm. So first thing you ‘re going to. To want to do is change the language of your project to Python, So inside of pycharm. Go to File > Settings > Project Settings and in the Languages section change Python to the language of your project. Now next thing you ‘re going to want to do is set up your project folder so inside of pycharm go to File > Settings > Project Structure and in the Project Folder section click on the Browse button and then select the folder where you want your project files to live so now Your project is set up and ready to go all right let’s start writing some code. We’re going to start with the simplest code possible and that’s a hello world program. In Python. A Hello world program is simply a program that prints out hello world so let’s open up our.py file and enter this code here. Here import sys [UNK] world!”) all right so we’ve imported the Sys module and then we’ve printed out [UNK] world!” now Let’s save our file by clicking on this green button here in your editor window and call it Hello.py now let’s run our program by clicking on this green run button here inside of pycharm and you’ll see that our program has printed out [UNK] world!” all right that’s our first simple code block in Python now Let’s take a look at some more code blocks in Python. First thing we’ll want to do is create a variable, so let’s open up our hello.py file again and enter this code def [UNK] [UNK] world!”) all right so we’ve defined a function called say —hello() and inside of say —hello() we’re going to print out [UNK] world!” now let’s save our file once again say we want to declare a variable called price. We would type price and then after we type the name of the variable. We would put a colon and then the value of that variable. So in this case, the value of this variable will be 12.99. So we can use this variable anywhere inside our Python code now let’s say we want to print the value of this variable. We can do that by simply writing print price and then after that we would put a period and then the value of the variable. So in this case the code would print out 12.99 alright. Now let ‘s say we wanted to change the value of this variable. We can do that by simply typing new value for price and then after that we would type a colon and then the new value of the variable. So in this case the code would print out 13.00 alright. Now let’s say we wanted to delete this variable. We can do that by simply typing delete price and then after that we would type a period and then hit enter so In this case, the code would delete the variable called price Alright. Now let’s talk about lists. Let’s say we have a list of items and we want to display. each item in turn on our application window so to do that we need to use a for loop so to declare a for loop. We would type for item in list, and then after that we would type parenthesis, then the list item and then after that hit enter so In this case, the code would run for each item in the list called list and then it would go inside the parentheses and it would assign the item inside those parentheses to the variable called item. So in this case, the code would print out apple Banana cherry pineapple, so you can see how this works if you wanted to change what was inside those parentheses. You could do that by simply typing different values for parenthesis. So in this case, I typed apple Banana cherry pineapple. So now you understand how to use a for loop alright. Now last but not least let’s talk about functions. Functions are blocks of code that you can use in your python programs to simplify your code or to make it more powerful. You can think of functions as mini-programs inside your python program, So you can see here is a function called square which is just a simple function that takes one parameter which is called a number, and it returns the square of that number. Okay now let’s say we wanted to call this function inside our for loop so to do that we would type square(12.99) inside our for loop and after that hit enter so. In this case the code would run and it declare and use variables in python.
You run the program and you get this message. The age of John Smith is 1990 okay. So this is how we can use the input function in Python to read a value from the user now. In addition to reading values from the user, we also have the ability to write values to the user. So let me show you how we do that so we first create a variable called message and set it to the string ‘please enter your message’ now we use the print function to print our message on the terminal window so you can see it here now. Let’s run our program and see what happens so please enter your message so we get this message now. What we want to do is display this message for as long as the user remains in our program. So we use the while loop so we type while True which means while the condition is True. So In this case the condition is that our message variable is not empty and that ‘s why we put a comma after while because that ‘s what tells Python to keep looping while this condition is met okay now if you type exit out of our program right now you will get an error message because our while loop condition is not met Okay. So now let’s add a counter to our program. So we can keep track of how many times our while loop condition has been met. So we add a variable called counter and set it to 1. Now if you run our program again and type exit out. of it, you will see that our while loop condition has been met four times. Now Let’s add another counter and set it to 2 now. If you run our program again and type exit out of it. You will see that our while loop condition has been met six times now let’s add another counter and set it to 3. Now If you run our program again and type exit out of it, you will see that our while loop condition has been met nine times now finally let’s add another counter and set it to 4. Now. If you run our program again and type exit out of it. You will see that our while loop condition has been met 12 times. So this is how we can use the while loop in Python to write a value to the user. So next time I ‘ll show you how to read values from the user and how to write values to the user. THe passage discusses how an error occurred in a program. THe error was caused by attempting to subtract a string from an integer, which Python does not support. TO solve the problem, the author converted the string to an integer and solved the problem.. function is the string that we got from the input function now let’s run the program so 10 and 20.1 and here ‘s the result In. This passage, the author explains how to solve a problem in Python where two numbers are being combined together as strings.. THe first number is read into a variable, and the second number is read into a second variable.. THe sum of the two numbers is then calculated using the float function, which converts both numbers to their. numeric representations. Finally, the sum of the two numbers is displayed on the terminal. One way to solve This problem would be to use the int function, which would convert both numbers to integers. However,. Since we’re dealing with strings, we need to use the float function instead. Additionally,. Since we’re not required to use the float function, we could have just called it at the time. We wanted to calculate the sum of the two numbers. IN conclusion,. This passage provides some insights into how to solve a problem in Python where two numbers are being combined together as strings.. The first step is to read in the first number into a variable, and the second step is to read in the second number.. The sum of the two numbers is then calculated using the float function, which converts both numbers to their numeric representations.. Finally, the sum of the two numbers is displayed on the terminal..
Ia, you can see the course variable has been updated to say y y y y now I ‘ll delete that line and let’s run the program again. You should see two now. We can also use the find method to look for a specific character in our string. So if we wanted to find the character at index 3 in our string. We could do course.find(3) and as Ia you can see that function returned the value 4. So this is another really useful function for finding specific values in strings. Now let’s take a look at one last function called split and this function will take a string as input and it will split that string into an array of characters. So if we pass course.split() as ia, you can see that function has divided our string into an array of three characters. Now let’s use this array. to do some math. We can use the len function to get the length of our array and then we can use the range function to see if our number is between 0 and 9. So in this case our number is 5. So we would type 5, 6, 7, 8, 9, and so on now. This is a really useful function because it allows us to do basic math operations on strings without having to worry about the individual characters in the string okay so that’s all for today folks thank you for watching look at the first one so in this case, we have division with one slash so what this operator is going to do is it ‘s going to divide the first number by the second number and that’s it so let ‘s print 5 divided by 2. This is going to print 1 because 5. is going to be divided by 2. Which is 1. Now let’s look at the second division operator. Let ‘s print 10 divided by 3. This is going to print 3 because 10 is going to be divided by 3. Which is 3. Now let’s look at a final example. In this case, we have a string that has two integers in it 10 and 5 and we want to divide them. So in Python. We can use the / operator, so we can write 10 / 5. This is going to print 2. Because 10 is going to be divided by 5. Which is 2.’m going to declare a variable called a and set it to 10 plus 5 and then I ‘m going to declare another variable called b and set it to 5.. Now what we want to do is we want to compare or compare these. two values, so we can use the == operator. So this is equal to or it’s the same as the regular assignment operator, but it also works with comparison operators. So in this case it’s going to return True. If these two values are equal and False if they’re not equal. all right. Let me ask you another question suppose I have a variable called x and I set it to 10.5. Now what do you think is the result of this expression. This is again a basic math question that unfortunately, a lot of people fail to answer. The answer is 15.5 because 10.5 plus 5.5 equals 15.5.
This expression is going to be false because the value of price is 5.. Then we ‘re going to have another Boolean expression price less than 30 and the result of this expression is also going to be false because price is 10. then we ‘re going to have the not operator and the result of this expression is going to be true because price doesn’t equal 10 or 5.. So these are the five comparison operators that you ‘ll see in Python. You can also use these operators in combination with each other. So for example, if we wanted to compare the value of x to 3, we could use greater than or equal to followed by less than or equal to and then we could use the equality operator right after that so that’s a little bit more detail on these comparison operators in Python. go back to. Our if statement and let’s say if temperature is not greater than 30, We want to print a message saying it ‘s not a hot day, so we type if then we type a condition and this is where we use our comparison operators, So we type temperature not greater than 30.. Then so we add a colon and see what happens when I press enter now the character is indented and this represents a block of code. So the code that we write over here will be executed If this condition is true otherwise it’s not going to be executed. Let me show you so we ‘re going to print. It ‘s not a hot day and by the way note that here i’ve surrounded the string with double quotes. Because here we have a single quote as an apostrophe, so I could n’t declare a string like this. with single quotes If I typed it ‘s not a hot day look Python gets confused because it thinks this single code represents the end of our string, so it doesn’t recognize the subsequent characters okay so that ‘s why we use double quotes here so we can have an apostrophe in our string, so it ‘s not a hot day Now If I press enter again. The carrot is indented so the code that right here will be part of our if block and it will get executed. If this condition is true. So here we can print a second message drink plenty of water now to terminate this block. We press enter and then press shift and tab. The carrot is no longer indented. So the code that we write here will always get executed no matter what whether this condition is true or not okay. Now in C-based programming languages like C plus C, sharp, Java and Javascript. We present a block of code using curly braces. So you start a block of code using a left brace and then end it using a right brace. In python we do n’t have curly braces. So we use indentation to represent a block of code okay so in this case. These two lines are indented and that means they are part of this block of code. Now let ‘s go back to our if statement and let’s say if temperature is greater than or equal to 30, then we want to print a message, saying it’s cold today. So we type if then we type another condition and this is where we use. Our comparison operators so we type temperature greater than or equal to 30.. Then so we add an equals sign and see what happens when I press enter now. The character is indented and this represents a block of code. So the code that we write over here will be executed only if this condition is true in kilograms. So I type K and press enter now. It tells me to multiply the weight by 2.2 to get the pounds. So I type m and press enter now. It says to divide the weight by 12 to get the kilograms so I type KD and press enter now It asks me if I want to convert to pounds or kilograms. So I type P and press enter now. It tells me the result in pounds. So I type P and press enter again. Now let’s take a look at our. If statement here we have three conditions. One is that the weight is in kilograms. The second is that the weight is in pounds and the third is that the weight is between 170 and 220. So. If any of these conditions are met, then we’re going to print a message saying the weight is in this range okay, so what we have here is a range of weights from 170 to 220, so we can print it says the weight is in this range.
170 in pounds 170 in kilograms. THe insights that can be gleaned from this passage are as [UNK] [UNK] while loop can be used to repeat a block of code multiple times. [UNK] condition in the while loop must be true for the code in the block to get executed. [UNK] the variable i within the while loop is necessary for it to keep track of the counter. tell Python that we are declaring a list and then we assign it the value of a list. So in this case. Names is a list of strings okay now let me show you how we would print out the contents of the list names so I ‘m going to use the print function and I ‘m going to use the string format, so I ‘m going to tell Python to print the list value and then I ‘m going to use. an asterisk to indicate that I want to print every element in the list. Okay so now Let me change this program so that it prints out the names of all the students in my class. So here we are creating a new variable called students and we’re assigning it the value of a list, which is a list of strings. Okay. Now let me run this program and we see that it’s printing out all the students in my class. Okay now let me change this program so that it prints out the average grades of all the students in my class. So here we are creating a new variable called grades and we’re assigning it the value of a list, which is a list of floats. Okay Now let me run this program and we see that it’s printing out the average grades of all the students in. My class okay now Let me create a new file called practice.py and I am going to import some modules. So first I am going to import the math module so we can use mathematical operations like addition, subtraction,, multiplication, and division In. This passage, you learn about three types of data in [UNK] numbers, Booleans,, and strings. You learn about lists, which are used for representing a list of objects.. You also learn about print functions and string formats..
can use them to store multiple items in a single variable, but the difference is that tuples are immutable. So once we create a tuple, it’s always going to be the same no matter what we do with it So let me show you an example so let’s say we want to create a tuple that contains the numbers 2, 3 and 5. We can do this by typing (2, 3, 5) and this is going to create a tuple that contains the values 2, 3 and 5. Now If we wanted to change the value of the first item in the tuple. We would type (2, 3, 5) and this would change the value of the first item in the tuple. So it would now contain the value 4 take a look here. You go so tuples are kind of like lists, but they are immutable so you can’t. change the value of the first item in a tuple once you create it now another thing that you might want to keep in mind is that tuples can be used as input parameters for functions. So for example, let’s say we want to create a function that takes two tuples as input parameters and it’s going to print out the sum of the items in each tuple okay So let’s say we want to create a function called add —two —tuple that takes two tuples as input parameters and it’s going to print out the sum of the items in each tuple okay. So we can do this by first creating a function called function —name and then inside of function —name. We can type def add —two —tuple and then inside of add —two —tuple. We can type (1, 2) and (3, 4) and this is going to create a function that expects two input parameters. a tuple consisting of one item and a tuple consisting of two items now. If we wanted to call our add —two —tuple function from within another Python script, we would do something like this take a look here you go now. If we wanted to call our add —two —tuple function from within our main script. We would do something like this import function —name function —name.add —two —tuple( (1, 2), (3, 4)) now you might be wondering how you’re supposed to pass two tuples as input parameters to a function if they’re not stored in variables like numbers or strings right well. Fortunately, Python has a special type of variable called an instance variable and an instance variable is basically just like any other variable except it’s associated with a particular object. So for example, if we Tuples are immutable, and can’t be changed once they’re created. Tuples can be used to store sequences of objects,. But they are unchangeable once they’re created. When defining a list of numbers, square brackets are used to define a list, and parentheses are used to define a tuple.. IF. We try to reassign the first element of the tuple, we’ll get an error. IF. We want to modify a tuple, we need to use the methods that start with an underscore, such as count and index..