## 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

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
```
OperatorExplanationResult
== It returns true if the value of two operands are equal and false if two operands are not equalfalse
!= It returns true if the value of two operands are not equal and false if two operands are equaltrue
> It returns true if the value of left operands is greater than right operand else it returns falsetrue
< It returns true if the value of left operands is less than right operand else it returns falsefalse
>= It returns true if the value of left operands is greater than or equal to right operand else it returns falsetrue
<= It returns true if the value of left operands is less than or equal to right operand else it returns falsefalse

## 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
>>> ```

## Python Assignment Operators

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

OperatorExplanation
+=Add right operand to left and assigns addition to the left operand
-=Subtract right operand from left and assigns subtraction to the left operand
*=Multiply right operand to left and assigns multiplication to the left operand
/=Divide right operand by left and assigns division to the left operand
%=Divide right operand by left and assigns remainder of division to the left operand
//=Divide right operand by left and assigns results of division to the left operand by removing digits after the decimal point
**=Perform exponential calculation of two operands and then assign result to left operand.

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

OperatorExplanationExample
+It is used to perform addition of two numbers num1 + num2 will give 15
It is used to perform subtraction of two numbers num1 – num2 will give 5
*It is used to perform multiplication of two numbers num1 * num2 will give 50
/It is used to perform division of two numbers num1 / num2 will give 2
%It is used to perform modulo operator where num1 is divided by num2 and remainder will be returned num1 % num2 will give 0
**It is used to perform exponential calculation of two numbers num1 ** num2 will give 10 to the power 5
//It is used to perform floor division of two numbers 10//2 will give 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.

OperatorExplanation
10 // 3Result of the operation is 3 mathematically in case of integer division. Floor division also provide result = 3
10.0 // 3Result of the operation is 3.33 mathematically but using floor division result would be 3, as it removes digits after decimal point

## 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
>>>
```