BITAND

Finds the bitwise ‘AND’ value of two numbers and returns it.

Syntax:

BITAND(numberOne, numberTwo)

numberOne and numberTwo must be a decimal and should be 0 or higher.

Example:

If numberOne contains 1 and numberTwo contains 2:

BITAND(1, 2)

returns 0

numberOne:

numberTwo:

Result:

0

Application:

The BITAND function is often used in computer science and data analysis for tasks involving bitwise operations, particularly when dealing with flags or permissions. A great application of using the BITAND function is when someone is managing a system where users have different levels of access.

Let's imagine a small company with a simple file sharing system. Each user has a set of permissions, which we can represent as a single number using bit flags. Each bit in this number corresponds to a specific permission.

Here's how we can set it up:

Permission 1 (Bit 0): Read Access = 1
Permission 2 (Bit 1): Write Access = 2
Permission 3 (Bit 2): Delete Access = 4
Permission 4 (Bit 3): Administrator Access = 8

A user's total permissions are the sum of the permissions they have. For example:

A user with Read and Write access would have a total permission value of 1 + 2 = 3.
A user with Read and Delete access would have a total permission value of 1 + 4 = 5.
An administrator (who has all permissions) would have a value of 1 + 2 + 4 + 8 = 15.

The Problem

Now, let's say we want to check if a user has a specific permission, for instance, "Write Access." We can use the BITAND function for this. BITAND compares the bits of two numbers and returns a new number with bits set to 1 only if both corresponding bits in the original numbers are 1.

The logic is: If BITAND(User's_Permission_Value, Permission_to_Check_Value) is equal to Permission_to_Check_Value, then the user has that permission.

Example Table

Let's set up a simple table to demonstrate this.

	User ID	User Name	Permission Value
	A	B	C
1	101	Alice	3
2	102	Bob	5
3	103	Charlie	15
4	104	David	2

Now, let's add a column to check for "Write Access" (which has a value of 2).

The formula we would use in cell D1 (for Alice) is:

IF(BITAND(C1, 2) = 2, "Yes", "No")

Let's break down what's happening for each user:

Alice (Permission Value = 3):
- In binary: 3 is 0011 and 2 is 0010.
- BITAND(3, 2) compares the bits:
  0011 (Alice's permissions)
  & 0010 (Write access flag)
  -----
  0010 (Result is 2)
- Since the result 2 is equal to the permission value 2, the formula returns "Yes".

Bob (Permission Value = 5):
- In binary: 5 is 0101 and 2 is 0010.
- BITAND(5, 2) compares the bits:
  0101 (Bob's permissions)
  & 0010 (Write access flag)
  -----
  0000 (Result is 0)
- The result 0 is not equal to 2, so the formula returns "No".

Charlie (Permission Value = 15):
- BITAND(15, 2) results in 2, so the formula returns "Yes".

David (Permission Value = 2):
- BITAND(2, 2) results in 2, so the formula returns "Yes".

Here's what the final table would look like:

	User ID	User Name	Permission Value	Has Write Access?
	A	B	C	D
1	101	Alice	3	Yes
2	102	Bob	5	No
3	103	Charlie	15	Yes
4	104	David	2	Yes

This example shows how BITAND can be a powerful tool for efficiently checking for the presence of specific attributes or flags stored in a single numerical value, avoiding the need for multiple columns for each permission.