How to read bits from a file?

Question

I know how to read bytes — `x.read(number_of_bytes)`, but how can I read bits in Python? I have to read only 5 bits (not 8 bits [1 byte]) from a binary file Any ideas or approach?

Accepted Answer

Python can only read a byte at a time. You'd need to read in a full byte, then just extract the value you want from that byte, e.g.

```
b = x.read(1)
firstfivebits = b >> 3
```

Or if you wanted the 5 least significant bits, rather than the 5 most significant bits:

```
b = x.read(1)
lastfivebits = b & 0b11111
```

Some other useful bit manipulation info can be found here: http://wiki.python.org/moin/BitManipulation

How to read bits from a file?

Solution

Problem