Difference between revisions of "Global & Parameter Passing - Python"
(Created page with "=Global Variables= One way to pass values into subroutines is by using global. In the example below we have declared a variable and we have 2 subroutines which use this, one t...") |
(→Global Variables) |
||
Line 32: | Line 32: | ||
This code will print '42' because the variable will be changed in func1(). | This code will print '42' because the variable will be changed in func1(). | ||
+ | |||
+ | =Parameters= | ||
+ | |||
+ | In python a subroutine can have parameters which must be passed into the subroutine when it is called. Failure to do so will cause a syntax error. | ||
+ | |||
+ | =Default Parameters= | ||
+ | You can specify a default value for a parameter, this will be used if no parameter is passed. For example: | ||
+ | |||
+ | <syntaxhighlight lang=python> | ||
+ | def my_function(country = "Norway"): | ||
+ | print("I am from " + country) | ||
+ | |||
+ | my_function("Sweden") | ||
+ | my_function("India") | ||
+ | my_function() | ||
+ | my_function("Brazil") | ||
+ | </syntaxhighlight> |
Revision as of 22:49, 25 June 2018
Global Variables
One way to pass values into subroutines is by using global. In the example below we have declared a variable and we have 2 subroutines which use this, one to just print and the other to change the value:
myGlobal = 5
def func1():
myGlobal = 42
def func2():
print myGlobal
func1()
func2()
This program will actually print '5' and not 42, because the change within func1() is not retained. However it will be if you add a global command:
myGlobal = 5
def func1():
global myGlobal
myGlobal = 42
def func2():
print myGlobal
func1()
func2()
This code will print '42' because the variable will be changed in func1().
Parameters
In python a subroutine can have parameters which must be passed into the subroutine when it is called. Failure to do so will cause a syntax error.
Default Parameters
You can specify a default value for a parameter, this will be used if no parameter is passed. For example:
def my_function(country = "Norway"):
print("I am from " + country)
my_function("Sweden")
my_function("India")
my_function()
my_function("Brazil")