Python Dictionary : clear()

1. In order to remove the all items from the dictionary we use clear().
2. It does not take any parameter
3. Method does not return any value.

Syntax

Below syntax is used for clear() method -

dict.clear()

Python Dictionary : clear() Example

#!/usr/bin/python
dict = {'Word1': 'Meaning1', 'Word2': 'Meaning2'};
print ("Dictionary Length : %d" %  len(dict))
dict.clear()
print ("Dictionary Length : %d" %  len(dict))

Output :

After running the program we will get below output -

>>> 
Dictionary Length : 2
Dictionary Length : 0
>>> 

Python comparison operators are used to compare the two numbers. Python comparison operators are very useful in decision making

Python comparison operators :

#!/usr/bin/python
num1 = 20 > 10;
num2 = 20 < 10;
num3 = 20 == 10;
print ("Line 1 - Value of num1 : ", num1)
print ("Line 1 - Value of num2 : ", num2)
print ("Line 1 - Value of num3 : ", num3)

Output :

>>> 
Line 1 - Value of num1 :  True
Line 1 - Value of num2 :  False
Line 1 - Value of num3 :  False
>>>

Some Python comparison operators

Consider the following values of num1 and num2

num1 = 10
num2 = 5

Python Examples : Comparison Operator

Example #1 : Comparison Operator

#!/usr/bin/python
res = 20 == 10;
print ("Line 1 - Value of res : ", res)
res = 20 != 10;
print ("Line 2 - Value of res : ", res)
res = 20 > 10;
print ("Line 3 - Value of res : ", res)
res = 20 < 10;
print ("Line 4 - Value of res : ", res)
res = 20 >= 10;
print ("Line 5 - Value of res : ", res)
res = 20 <= 10;
print ("Line 6 - Value of res : ", res)

Output :

>>> 
Line 1 - Value of res :  False
Line 2 - Value of res :  True
Line 3 - Value of res :  True
Line 4 - Value of res :  False
Line 5 - Value of res :  True
Line 6 - Value of res :  False
>>> 

Example #2 : Comparison Operator

#!/usr/bin/python
num1 = 10
num2 = 5
if(num1 == num2)
   print ("Line 1 - True Condition")
else
   print ("Line 1 - False Condition")
if(num1 != num2)
   print ("Line 2 - True Condition")
else
   print ("Line 2 - False Condition")
if(num1 > num2)
   print ("Line 3 - True Condition")
else
   print ("Line 3 - False Condition")
if(num1 < num2)
   print ("Line 4 - True Condition")
else
   print ("Line 4 - False Condition")
if(num1 >= num2)
   print ("Line 5 - True Condition")
else
   print ("Line 5 - False Condition")
if(num1 <= num2)
   print ("Line 6 - True Condition")
else
   print ("Line 6 - False Condition")

Output :

>>> 
Line 1 - False Condition
Line 2 - True Condition
Line 3 - True Condition
Line 4 - False Condition
Line 5 - True Condition
Line 6 - False Condition
>>> 

In this chapter we will be learning about Python assignment operators and some compound assignment operators supported in Python

Python Assignment operators :

Python Assignment operator is used for assigning the value of right operand to the left operand.

#!/usr/bin/python
num1 = 10
num2 = 20.20
num3 = 'A'
print ("Line 1 - Value of num1 : ", num1)
print ("Line 2 - Value of num2 : ", num2)
print ("Line 3 - Value of num3 : ", num3)

Output :

>>> 
Line 1 - Value of num1 :  10
Line 2 - Value of num2 :  20.2
Line 3 - Value of num3 :  A
>>> 

Python Compound Assignment Operators

Consider the value of num1 = 10 and num2 = 5

In these kind of compound assignment operators we are also performing indirect python arithmetic operations.

Example:

#!/usr/bin/python
num1 = 10
num2 = 5
res = num1 + num2
res += num1
print ("Line 1 - Result of + is ", res)
res *= num1
print ("Line 2 - Result of * is ", res)
res /= num1
print ("Line 3 - Result of / is ", res)
res //= num1
print ("Line 4 - Result of // is ", res)
res **= num1
print ("Line 5 - Result of ** is ", res)
res %= num1
print ("Line 6 - Result of % is ", res)
res -= num1
print ("Line 7 - Result of - is ", res)

Output :

>>> 
Line 1 - Result of + is  25
Line 2 - Result of * is  250
Line 3 - Result of / is  25.0
Line 4 - Result of // is  2.0
Line 5 - Result of ** is  1024.0
Line 6 - Result of % is  4.0
Line 7 - Result of - is  -6.0
>>> 

Python Arithmetic operators :

Python provides some arithmetic operators which perform the task of arithmetic operations. Below are some arithmetic operators -

Consider the value of num1 = 10 and num2 = 5

Floor Division :

In the Python floor division, when a number is divided by another number then digits after the decimal point of result will be removed.

Example:

#!/usr/bin/python
num1 = 10
num2 = 5
res = 0
res = num1 + num2
print ("Line 1 - Result of + is ", res)
res = num1 - num2
print ("Line 2 - Result of - is ", res)
res = num1 * num2
print ("Line 3 - Result of * is ", res)
res = num1 / num2
print ("Line 4 - Result of / is ", res)
res = num1 // num2
print ("Line 5 - Result of // is ", res)
res = num1 ** num2
print ("Line 6 - Result of ** is ", res)
res = num1 % num2
print ("Line 7 - Result of % is ", res)

Output :

>>> 
Line 1 - Result of + is  15
Line 2 - Result of - is  5
Line 3 - Result of * is  50
Line 4 - Result of / is  2.0
Line 5 - Result of // is  2
Line 6 - Result of ** is  100000
Line 7 - Result of % is  0
>>>