Functions, arguments, parameters, this step stores and uses. We define a program by defining the module thing that prints Hello, and fun. When we call it, it will print the two words. I have also placed another print and a new Call of the function thing. You can see on the right side, how it does this action whenever it is called. There are two kinds of functions in Python.

The built in functions provided by Python, raw underscore input, type, float, and etc. And also the functions we define in user cells. The names of embedded functions are considered as reserved words. They're not used to name variables. In Python, a function is reusable code that takes an input argument performs actions and returns one or more results. The function is defined with the reserved words Death.

A function is called by using its name, parentheses, and an argument in an expression. The argument of the max function is the text hello world. We signed this function and argument to the variable big. The result is W. Since this is the letter closer to the end of the alphabet, a function is a part of code. A function takes a certain input and produces an output, hello world is the input, while W is the output type conversion, when using an integer and a floating number, in an expression, the integer is implicitly converted to a floating point conversion as possible with the built in functions and add float. defining our own functions.

Create a new function using the keyword def followed by optional parameters in parentheses indent to Body of the function. This sets the function, but will not execute the body of the function. You can see a new example written on the slide, we have to find the print lyrics function. However, if we do not call it, then it does not perform its action, it just waits. So we can print other lines before calling it. When you call it by typing its name, it will also execute its commands.

You can try it on your own. Once the function is defined, we can call it or invoke it as many times as we want. It is the module store and reuse. An argument is the value that we pass into the function as input. When we call function. We use the arguments in order to direct the function to do different things when we call it at different times.

We put the arguments in parentheses after the function name. A parameter is a variable that we use in the definition of the function. This is a title that allows the code in the function to access arguments for invoking a particular function. I defined a function to greet people in different languages. You can see the example on the right side. Often a function will habits arguments will make calculations to return a value that will serve as a value to the function call in the calling expression.

This is the role of the return keyboard. A fruitful function is one that produces a result return of value. The return statement completes the execution of the function and returns the result of the function. The previous example has been modified to combinate the person's name a different example to show how parameters work, the max function allows a parameter that the function will work with inside the max function. This parameter can be put through a for loop to test what it is about, or to compute the difference between the letters of the parameter, so that it can return the correct outcome, which for this case is W. More than one parameter can be defined in the function definition, I have simply added more arguments when calling the function, we adopt the number and order arguments and parameters, I have defined the addition function to have two parameters, then called the function with the parameters three and five, that function will add them and return the result.

When a function does not return a value, it is called the void. functions that return values are fruitful, void functions are unsuccessful. The interpreter executes the instruction lines off the program, one after the other in the order in which they appear in the source code. In the script, the definition of the functions must therefore precede their use. If double honor dash name, double under dash two equal signs double under dash mean double under dash place at the end of the module. It is used to determine whether the module is started as a program, in which case, the following instructions must be executed or used as a class imported elsewhere.

In this case, this part of the code has no effect. Here is a working example for you define a change car CH, c one, C two start and function that replaces all the CA one characters with C two characters in the CH character string from the beginning index to the final index. The last arguments can be omitted, and in this case, the string is processed from one end to the other. Organize your code as paragraphs by capturing a complete thought and name it. Do not repeat, make it work once and then reuse. If something becomes too long or too complex, separated into logical parts Put these pieces into function.

Both a library of operations that you repeat continually, maybe shared with your friends. A function can accept any number of parameters, their names do not matter much. They're used to name the values transmitted when calling the function locally. On the other hand, the order in which these parameters appear in the definition of the function is important. A default value can be given to one or more arguments of a function. For this purpose, in the definition of this function, and if we denote by arc the name of the argument, and about its default value, we will replace arc by arc is equal to Val.

If an argument receives a default value, it can be omitted when calling the function but for there not to be ambiguous. arguments with default values in the definition of the function must follow those that do not lie. to function in Python, a lambda function is an anonymous function to which no name has been given. The syntax is lambda parameters expression. Note, lambda is one of the reserved words of the language, the lambda function must be on a single line and cannot contain compound statements, no assignments, no loops, etc. You can find here examples of using the lambda function in the first example, and maps all of the result of multiplying the first 10 numbers with themselves.

Can you guess what happens in the second function filter? Not filter are functions for processing interations typical a functioning programming filter takes the function as a parameter often a lambda, it must return true if we keep an element and false otherwise. In this example, the filter function prints the ages that are higher than 18 But lower than 30. The same can be done with the statement found on the last row of the image. The map function transforms the list using a callback function. The actual perform with filter can also be performed with map.

However, the parameters of the pendant method are different. Now this callback of each element of the new list, the first example listed at the lower side of the slide will print each character and uppercase. It's written both the map function and with the loop. The second example will give each of the H m s variable, a value corresponding to the number in the string 819 22. Again, same function can be done with a for loop exercise, write a function giving the sum of the integers from one to n, which are divisible by three or five, mutable and immutable. An object is mutable when it is possible to modify it, an object is immutable when it is impossible to modify it.

When doing operations on immutable objects to obtain a new value, one is obliged to construct another object. Because the operations do not make it possible to modify the original mutable objects provide operation to modify the value contained in the object, retaining the same object, you can see some examples of mutable and immutable objects. In the bottom left example, the variable is immutable. Even if you change the value of the variable, its ID remains the same, while in the bottom right. They're immutable. When you add a text to the string, its ID changes.

Try to see which are immutable and which are not from the examples on the right side. They're immutable objects are numeric values, strings, and tubes. The interest of immutable objects That one is sure that no one can change their value. All names referencing an immutable object may consider it to be constant, as long as they continue to reference it. Beautiful objects are lists and dictionaries. Genuinely, the other objects, those you create, are also immutable.

The names that reference mutable objects can see the object by reference, modified by function called by code executed in another thread, passing parameters. In Python, and Python, all parameters are passed by references to objects. These references being associated with the names of the parameters during the call. The change from immutable value to a parameter can be used to carry out a value return. For example, an empty list is passed and the function fills that but to avoid as much as possible, it is better to have an explicit return of a value rather than based More or less hidden effect.