Write down all combinations of binary string

Question

I have a string of length 5. Each element of the string can take on two values 0 and 1.

I would like to write down all possible permutations.

For example:

There are 2^5 such combinations.

I know there is a command called combn but I do not know how to handle the fact that each digit can take on two possible values.

If you want a fast solution you could also try `data.table` `CJ` function. I.e, `library(data.table); CJ(0:1, 0:1, 0:1, 0:1, 0:1)` — David Arenburg, Aug 19 '14 at 08:39

score 5 · Answer 1 · answered Aug 19 '14 at 07:30

Perhaps not the best way to do it, but it works:

> expand.grid(0:1, 0:1, 0:1, 0:1, 0:1)
   Var1 Var2 Var3 Var4 Var5
1     0    0    0    0    0
2     1    0    0    0    0
3     0    1    0    0    0
4     1    1    0    0    0
5     0    0    1    0    0
6     1    0    1    0    0
7     0    1    1    0    0
8     1    1    1    0    0
9     0    0    0    1    0
10    1    0    0    1    0
11    0    1    0    1    0
12    1    1    0    1    0
13    0    0    1    1    0
14    1    0    1    1    0
15    0    1    1    1    0
16    1    1    1    1    0
17    0    0    0    0    1
18    1    0    0    0    1
19    0    1    0    0    1
20    1    1    0    0    1
21    0    0    1    0    1
22    1    0    1    0    1
23    0    1    1    0    1
24    1    1    1    0    1
25    0    0    0    1    1
26    1    0    0    1    1
27    0    1    0    1    1
28    1    1    0    1    1
29    0    0    1    1    1
30    1    0    1    1    1
31    0    1    1    1    1
32    1    1    1    1    1

thank you for this solution. the only problem is that it is very slow if you want to apply it to larger strings, for example 20. — upabove, Aug 19 '14 at 08:06
@user2733997, I was sure hat there is some special function for this (that's why I wrote perhaps not the best way), just wanted to show a simple alternative that came to my mind. — talat, Aug 19 '14 at 08:11

score 3 · Accepted Answer · answered Aug 19 '14 at 07:34

3

You can get your all 2^5 = 32 combinations by using :

install.packages('gtools')
library(gtools)
permutations(2,5,v=c(0,1),repeats.allowed=TRUE)

answered Aug 19 '14 at 07:34

Sangram

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this solution is much faster for higher values, for example if the string is of length 50. – upabove Aug 19 '14 at 08:06

Write down all combinations of binary string

2 Answers2