swap letters 2 by 2 in a string.

how cani i swap letters 2 by 2 in a string?. (in other word: abcdefg would become badcfeg)

Answer 1

[Matt Fig]

S = 'abcdefg'
S = S([2 1 4 3 6 5 7])

Or, generally:

for ii=1:2:numel(S)-mod(numel(S),2),S([ii,ii+1])=S([ii+1,ii]),end

[Mohammed]

it works, but the for loop make the string repeat 9 times!

[Matt Fig]

What do you mean it repeats 9 times? When I run that FOR loop then type:

>> S

S =

badcfeg

No repeating 9 times here. Do you mean that it displays several times during the loop? Simply put a semicolon in after the assignment in the loop. I left it out so you could see what was going on. I assumed you would know to put it back in if you wanted to do so. I.e., instead of:

S([ii,ii+1])=S([ii+1,ii]),

use:

S([ii,ii+1])=S([ii+1,ii]);  % Notice the ; instead of ,

Incidentally, I like this one better:

for ii=2:2:numel(S),S([ii-1,ii])=S([ii,ii-1]);end

Answer 2

[Sean de Wolski]

str = 'a':'g';
eo  = mod(numel(str),2); %even odd
str(1:end-eo) = flipud(reshape(str(1:end-eo),2,[])) %swap

Answer 3

[Azzi Abdelmalek]

s='abcdefg';
m=fix(numel(s)/2)*2
s(1:m)=reshape(flipud(reshape(s(1:m),2,[])),1,[])