Find all upper, lower and mixed case combinations of a string

Question

I want to write a program that would take a string, let's say "Fox", then it would display:

fox, Fox, fOx, foX, FOx, FoX, fOX, FOX

My code so far:

string = raw_input("Enter String: ")
length = len(string)
for i in range(0, length):
    for j in range(0, length):
        if i == j:
            x = string.replace(string[i], string[i].upper())
            print x

Output so far:

Enter String: fox
Fox
fOx
foX
>>> 

Answer 1

import itertools

s = 'Fox'
map(''.join, itertools.product(*zip(s.upper(), s.lower())))
>>> ['FOX', 'FOx', 'FoX', 'Fox', 'fOX', 'fOx', 'foX', 'fox']

Answer 2

I always wanted to try this.

No idea if this fits your qualifications(it does work though).

str = raw_input()

def getBit(num, bit):
   return (num & 1 << bit) != 0

for i in xrange(0,2**len(str)):
   out = ""
   for bit in xrange(0,len(str)):
      if getBit(i,bit):
         out += str[bit].upper()
      else:
         out += str[bit].lower()

   print(out)

The idea is that as you increment in binary, you get every possible permutation of 1s and 0s.

Then you simply convert this list of 1s and 0s to a string, 1 meaning uppercase, 0 meaning lowercase.

Answer 3

This is the excellent, accepted answer by @ephemient modified a little bit.

Changes:

• lower-case before upper-case, just so the list starts with "fox" instead of "FOX" (the question's example sequence starts with "fox")

• use of a list comprehension instead of map() (either way is fine, really)

• broke out the code that generates the lower/upper case pairs to make it more clear

• packaged it up into a function.

The code:

import itertools as it

def cap_permutations(s):
    lu_sequence = ((c.lower(), c.upper()) for c in s)
    return [''.join(x) for x in it.product(*lu_sequence)]

Answer 4

One liner using list comprehension:

from itertools import permutations

strs='fox'
combin=[''.join(x) for x in permutations(list(strs)+list(strs.upper()),3) if ''.join(x).lower()=='fox']
print(combin)
>>> ['fox', 'foX', 'fOx', 'fOX', 'Fox', 'FoX', 'FOx', 'FOX']

Using a for loop:

from itertools import permutations

strs='fox'
lis2=list(strs)+list(strs.upper())

for x in permutations(lis2,3):
    if ''.join(x).lower()=='fox':
        print(''.join(x))

>>> fox
    foX
    fOx
    fOX
    Fox
    FoX
    FOx
    FOX

Answer 5

Use product (False, True) to find any permutations of change char in string for upper & lower:

def capitalize_char_permutation (string:str) -> str :
    conditions = product((0,1), repeat=len(string))
    for i in conditions:
        result = ''
        for j in range(len(i)):
            if i[j]==0 :
                result+= string[j].lower()
            else:
                result+= string[j].upper()
        yield result

Answer 6

Although what I tried is in c++, I guess you will get the logic. I was stuck in the same question so I searched around and this is what I ended up writing...I know it is not perfect and I would love if someone helps me make this code better and point out my mistakes.

#include <bits/stdc++.h>

using namespace std;

string decToBinary(int n,int l) 
{ 
    string ret="";
    for (int i = l-1; i >= 0; i--) { 
        int k = n >> i; 
        if (k & 1) 
            ret=ret+"1"; 
        else
            ret=ret+"0";
    }
    return ret; 
}

int main()
{
    string x;
    cin>>x;
    transform(x.begin(), x.end(), x.begin(), ::tolower); 
    int size=x.length();
    string bin;
    for(int i=0;i<pow(2,size);i++)
    {
        bin=decToBinary(i,size);
        for(int j=0;j<size;j++)
        {
            if(bin[j]=='1')
                cout<<(char)(x[j]-32);
            else
                cout<<x[j];
        }
        cout<<endl;
    }
}

Suppose the word "dog"...so, there will be 2^(number of letters) i.e. 2^3=8 combination. So, in this program, we iterate from 0-7 and convert the iterator(i in this case) to binary, for example, take the fifth iteration the binary would be 101 then the resultant word would be DoG (taking 1 as upper case and 0 as the lower case)..like this you can get all 2^n resultant words.

Answer 7

I combined @ephemient's solution, @steveha's solution, and my own tweak.

def allcasecombinations(s):
    return list({''.join(x) for x in itertools.product(*zip(s.upper(), s.lower()))})

my improvement is using a set and then converting it to a list. the set is to remove duplicates: for example if your string had punctuation, the original function would have duplicates (because " ".upper() == " ".lower()). I incorporated @steveha's work cause I figured using list comprehension inside a set is cleaner than list(set(map(itertoolsmagic))). the list conversion probably isn't necessary for most use cases, but I added it to be safe.

>>> allcasecombinations("hi!")
['HI!', 'hI!', 'Hi!', 'hi!']