Bitshifting a value in python

Question

I have a value out of I²C register which is 2 bytes wide like 01C5 (as string). For my application, i have to swap high and low byte.

I tried it this way:

valueLow = hex(int(value,16) >> 8)
valueHigh = hex(int(value,16) & 0x0011)

but the results I get are now what they should look like.

Do you have a better solution?

check [this answer](http://stackoverflow.com/a/15036568/2365792) — Tim Rijavec, Jun 02 '15 at 11:22
Well you're &-ing `C5` with `11`. How is that supposed to work? Use `FF` instead. — Stefan Pochmann, Jun 02 '15 at 11:24

FinalState · Answer 1 · 2015-06-02T14:05:55.560

0

Use this to get the byte-swapped value:

swappedValue = hex(value<<8&0xff00 | value>>8&0x00ff)

or, if value is a string,

swappedValue = hex(int(value,16)<<8&0xff00 |int(value,16)>>8&0x00ff)

If you need a number (for I2C), try:

swappedValue = int(value,16)<<8&0xff00 | int(value,16)>>8&0x00ff

edited Jun 02 '15 at 14:05

answered Jun 02 '15 at 11:40

FinalState

Thanks that looks very elegant. But as "value" is a string it generates this message: TypeError: unsupported operand type(s) for <<: 'str' and 'int' Unfortunately applying "hex()" to "value" does also generate an error: TypeError: hex() argument can't be converted to hex – Creatronik Jun 02 '15 at 13:45

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