Merge a 1 x N array to a 1 x 1 array without using loop in MATLAB

Question

Hi,

I have a 1 x N double array and I would like to merge it to become a 1 x 1 array.

E.g. K = [0,1,1,1];

I want K to become K = [0111];

How do I do it?

Answer 1

in python:

''.join([str(i) for i in k]) '1234'

Answer 2

Here's a cute way of doing it in one line:

>> K = [1 2 3 4];
>> K*10.^(length(K)-1:-1:0)'
ans =
        1234

EDIT: new, super short way now.

Answer 3

From your example I'm guessing you just want to concatenate the elements of a vector (seeing that k=[0111] actually stores the number 111). Therefore if you want to keep them as they are, we use a string instead:

>> K = [0,1,1,1];
>> str = sprintf('%d', K)
str =
0111
>> whos str
  Name      Size            Bytes  Class    Attributes
  str       1x4                 8  char

Answer 4

Since you are merging an array of zeroes and ones into a single value, you're going to have trouble representing it properly as a double value. This is because any leading zeroes on the left hand side of the number won't be displayed when it's a double. However, you can represent the string of zeroes and ones as a character array. A neat little trick for doing this is as follows:

>> K = [0,1,1,1];
>> char(K+'0')

ans =

0111

When you add a vector of doubles (K) and a scalar string ('0'), the string gets converted to it's ASCII/Unicode value (48 in this case). K+'0' becomes the vector [48 49 49 49], and the CHAR function changes these values to their equivalent ASCII/Unicode characters, creating a character array.