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Introduction to Bitwise Operators

The Man Behind the Bit Mask

A *bit mask* is just a variable that aids you with bitwise operations. A bit mask can help you turn specific bits on, turn others off, or just collect data from an integer about which bits are on or off.

num = 0b1100 mask = 0b0100 desired = num & mask if desired > 0: print "Bit was on"

In the example above, we want to see if the third bit from the right is on.

- First, we first create a variable
`num`

containing the number 12, or`0b1100`

. - Next, we create a
`mask`

with the third bit on. - Then, we use a bitwise-and operation to see if the third bit from the right of
`num`

is on. - If
`desired`

is greater than zero, then the third bit of`num`

must have been one.

### Instructions

**1.**

Define a function, `check_bit4`

, with one argument, `input`

, an integer.

It should check to see if the fourth bit from the right is on.

If the bit is on, `return "on"`

(not `print`

!)

If the bit is off, `return "off"`

.

Check the Hint for some examples!