This technical blog is my own collection of notes , articles , implementations and interpretation of referred topics in coding, programming, data analytics , data science , data warehousing , Cloud Applications and Artificial Intelligence . Feel free to explore my blog and articles for reference and downloads . Do subscribe , like , share and comment ---- Vivek Dash
Friday, February 19, 2021
Commands for Finding Certain Data on a disk in R Language
Thursday, February 18, 2021
Python program to create lists with different types of elements
Sunday, February 14, 2021
Monday, January 4, 2021
Sunday, January 3, 2021
Wednesday, December 30, 2020
Monday, December 28, 2020
Applications of Big Data for effective Monitoring and Tracking Purpose in Various Sectors
Friday, December 25, 2020
Updating the elements of a List in Python
Thursday, December 24, 2020
Monday, December 7, 2020
Global Keyword in Python and its usage
Global Keyword in Python
Sometimes, the global
variables and the local variables have the same name. In such a case, the
function by default refers to the local variable and ignores the global
variable. Therefore, the global variable is not accessible inside the function
but it is present outside the function where it is globally accessible.
# Python program to demonstrate the concept of global and local variables, same
# name used for global and local variables in the sample code
var = 10 # this is global variable
def somefunction():
var = 20 # this is a local
variable
print(' value of variable =',var) # local var
somefunction()
print(' variable value =',var)
Output
value of variable = 20
variable value = 10
When the programmer/user wants
to use the global variables inside a function, he can use the keyword 'global'
before the variable in the beginning of the function body.
For example :
global var
In the given programmatic
method, the global
variable is made available
to the function and the
programmer can work with it
in whichever manner the programmer/user wishes to work with the provided object
or variable .In the following program, a method to see how to
work with a global variable
inside a function.
==================================
Program
A Python program to access
global variables inside a function and modify the values .
# accessing a global
variable inside a function
var = 10 #
this is a global variable
def somefunction():
global var #
this is a global variable
print(' global variable =
',var) # display global
variable
var = 20 #
modify global var value
print(' modified variable
value = ', var)
somefunction()
print(' global variable
value = ',var) # display
modified value
Output
global variable = 10
modified variable value = 20
global variable value = 20
When an issue arises when the global variable name and local variable names are same , the programmer/reviewer/user will face difficulty to differentiate between them inside a function .
For example, if there is a
global variable 'a' with some value declared above the function.... Then there
is a global variable 'a' with some value declared above the function. Here, the
programmer is writing a local variable
with the same name 'var' with some other values inside the function .
Consider the following code :
var = 10 # this is a
global variable
def myfunction():
var = 20 # this is a local variable
In a scenario, when the programmer wants to work with a global variable, then the programmer would use a 'global' keyword . Then the programmer can access only the global variable and the local variable is no more available .
The globals() function can be used to solve this problem of using
global variable which would solve the problem .This is a built-in function
which returns a table of current global variables in the form of a dictionary.
Program
# Python program to get a
copy of global variable into a
# function and work with it
# same name for global and
local variable
var = 10 #
this is a global variable
def myfunction():
var = 20 # this
var is a local variable
x = globals()['var']
print('global variable var =
', x)
print(' local variable var =
',var)
myfunction()
print(' global variable
value =',var)
Output
global variable var = 10
local variable var = 20
global variable var = 10