Given a number ,the task is to count the set bits of the given number in its binary representation.

**Examples:**

**Example1:**

**Input:**

given number =235

**Output:**

The total number of set bits in the given number 235 : 6

**Example2:**

**Input:**

given number =8

**Output:**

The total number of set bits in the given number 8 : 1

**Example3:**

**Input:**

given number =375

**Output:**

The total number of set bits in the given number 375 : 7

## Program to Count Set Bits in a Number in Python

There are several ways to count set bits in the binary representation of the given number some of them are:

- By checking bit by bit from end using modulus operator
- By checking bit by bit from end using & operator
- By converting into binary using bin() and using count() function to count set bits
- By converting into binary using bin() and using sum() function to count set bits

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### Method #1: By checking bit by bit from end using modulus operator

A simple method is to take each bit into consideration in a number (set or unset) and hold an counterÂ to track the set bits.

**Approach:**

- Set the variable say count to 0 to count the total number of set bits.
- We utilize the while loop.
- We’ll keep going till the number is bigger than zero (Condition of while statement)
- Using the % operator, we will determine whether the last check bit is set or not.
- If the check bit is 1, it indicates that the bit is set, and we increment the count.
- Divide the given number by 2.
- Print the count.

**Below is the implementation:**

def countSetBit(numb): # checking if the given number is greater than 1 if numb > 1: # Set the variable say setbitcount to 0 to count the total number of set bits. setbitcount = 0 # looping till number greater than 0 using while loop while(numb > 0): # We will get the last check bit whether it is set bit or not using % operator checkbit = numb % 2 # checking if the check bit is 1 or not # if the check bit is 1 then increment the setbitcount if(checkbit == 1): setbitcount = setbitcount+1 # divide the number by 2 numb = numb//2 # return the setbitcount return setbitcount # Driver code given_numb = 235 # passing given number to countSetBit function to # count the total number of set bits in the given number print("The total number of set bits in the given number ", given_numb, " : ") print(countSetBit(given_numb))

**Output:**

The total number of set bits in the given number 235 : 6

### Method #2: By checking bit by bit from end using & operator

A simple method is to take each bit into consideration in a number (set or unset) and hold an counterÂ to track the set bits.

**Approach:**

- Set the variable say count to 0 to count the total number of set bits.
- We utilize the while loop.
- We’ll keep going till the number is bigger than zero (Condition of while statement)
- Using the & operator, we will determine whether the last check bit is set or not.
- If the check bit is 1, it indicates that the bit is set, and we increment the count.
- Divide the given number by 2.
- Print the count.

We use **n&1** to check whether it is set bit or not.

**Below is the implementation:**

def countSetBit(numb): # checking if the given number is greater than 1 if numb > 1: # Set the variable say setbitcount to 0 to count the total number of set bits. setbitcount = 0 # looping till number greater than 0 using while loop while(numb > 0): # We will get the last check bit whether it is set bit or not using & operator # checking if the check bit is 1 or not # if the check bit is 1 then increment the setbitcount if(numb & 1): setbitcount = setbitcount+1 # divide the number by 2 numb = numb//2 # return the setbitcount return setbitcount # Driver code given_numb = 235 # passing given number to countSetBit function to # count the total number of set bits in the given number print("The total number of set bits in the given number ", given_numb, " : ") print(countSetBit(given_numb))

**Output:**

The total number of set bits in the given number 235 : 6

### Method #3: By converting into binary using bin() and using count() function to count set bits

**Approach:**

- First we convert the given number into binary using bin() function.
- Then we count total number of ‘1’s in the binary string using count() function
- Print the count

**Below is the implementation:**

def countSetBit(numb): # converting given number to binary reepresentatioon using bin() binNum = bin(numb) # we count total number of '1's in the binary string using count() function setbitcount = binNum.count('1') # return the setbitcount return setbitcount # Driver code given_numb = 235 # passing given number to countSetBit function to # count the total number of set bits in the given number print("The total number of set bits in the given number ", given_numb, " : ") print(countSetBit(given_numb))

**Output:**

The total number of set bits in the given number 235 : 6

### Method #4: By converting into binary using bin() and using sum() function to count set bits

**Approach:**

- First we convert the given number into binary using bin() function.
- We slice from 2 to end of the binary string using slicing (to remove 0b characters from binary string)
- Convert every character of binary string to integer using map and then convert it to list
- Then we count total number of ‘1’s in the binary string list using sum() function(because the binary string contains only 0 and 1)
- Print the count

**Below is the implementation:**

def countSetBit(numb): # converting given number to binary reepresentatioon using bin() binNum = bin(numb) # We will slice from 2 index to last index of the result returned by binary string binNum = binNum[2:] # Convert every character of binary string to integer using map # and then convert it to list binList = list(map(int, binNum)) # we count total number of '1's in the binary string using sum() function setbitcount = sum(binList) # return the setbitcount return setbitcount # Driver code given_numb = 235 # passing given number to countSetBit function to # count the total number of set bits in the given number print("The total number of set bits in the given number ", given_numb, " : ") print(countSetBit(given_numb))

**Output:**

The total number of set bits in the given number 235 : 6

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