Programming with Python Class 6



A function is a sequence of actions that perform an operation and that can be identified by a name.

The functions allow us

. have a more structured code

. avoid code repetition

. is the basis of structured programming

. can be reused with other programs


In Phyton we can create functions as follows

def function (.. list of parameters …):

… body of the function …

… Return…

Parameter list and return value are optional.

There is no difference between functions (that return a value) and procedures (without a return value) as it exists in other types of languages.



Create a function that returns true if the value passed to it is even

def spread (n):if n% 2 == 0:return true


return False

Keep in mind that Python does not use blocks to delimit the code.

To define the body of the function, indentation is used.

Also indicate that the type of the parameters is not defined nor of the value that is returned, with this it is achieved that the same function can work for different types of data.

Functions with default parameters


Functions can be defined with default parameters, if the parameter is not indicated in the call, the default value of the function definition will be taken.



def function (p, p2 = 1):
print (“parameter 1”, p, “parameter 2”, p2)

this function can be used

function (1,2)

or only with the first parameter

function (1)

in this case the second parameter will use the default value.

Internal functions

Python provides a number of predefined functions that can be used directly.

Some of these functions are

max (x, y) – get the maximum value

min (x, y) – get the minimum value

len (x) – get the number of characters in a string

Type conversion functions can also be used

int (“2”) – convert a string to an integer

str (22) – convert an integer to a string


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