Replacing/flipping any specfic binary bit of a column using python-CodePudding

I want to flip any specific bit of a dataframe that also doesn't affect the neighbour bits. For example, my dataframe look like this,

s = pd.Series(["01100", "10010", "11100", "10011"])
0    01100
1    10010
2    11100
3    10011

Now, I want it as (after flipping only the 3rd bit),

I know how to flip last position bit using panda string slice but not any specific position.

CodePudding user response：

Applying a python function that does that for every entry

s.apply(lambda s: bin(int(s, 2)^(2**(3-1)))[2:].zfill(len(s)))

Concatenating concatenating the flipped bit with the unchanged part

s.str.slice(0,-3)   s.str.slice(-3,-2).replace('0', 'a').replace('1', '0').replace('a', '1')   s.str.slice(-2)

CodePudding user response：

One way is to use Series.str methods:

s = s.str.slice(stop=2)   (1-s.str.get(2).astype(int)).astype(str)   s.str.slice(start=3)

print(s):

0    01000
1    10110
2    11000
3    10111
dtype: object

CodePudding user response：

Integers are a more natural representation than str for this binary bit-flipping exercise.

You call it "the 3rd bit", but conventionally we name it the 2nd, reserving the zeroth bit for the low-order units position. We wish to flip the kth bit with ^ XOR.

import pandas as pd
from functools import partial
fmt = partial(str.format, '{0:08b}')

k = 2
df = pd.DataFrame(dict(n=s.apply(int, base=2)))
df['binary'] = df.n.apply(fmt)
df['flipped'] = (df.n ^ 2 ** k).apply(fmt)
>>> df
    n    binary   flipped
0  12  00001100  00000100
1  18  00010010  00011010
2  28  00011100  00010100
3  19  00010011  00011011

CodePudding user response：

here is one way to do it use regex

#partitioned the string, so you can point out the bit you want to flip
# check the value of the bit, and accordingly flip with if-else
s.str.replace(r'(..)(.)(.*)',
              lambda x: x.group(1)  
              ('0' if x.group(2)=='1' else '1')
               x.group(3), regex=True )

0    01000
1    10110
2    11000
3    10111
dtype: object