creating a new column with three columns

hello everyone,

i have three columns with 25 rows each. Now I want to merge all the three columns to one in a way that the first three rows will be the 1st values of all the three columns.

for ex: col_1, col_2 col_3 I need New merge col

25 22 23 25

26 25 20 22

24 28 30 23

26 and so on

so at last i will get one column with total of 75 rows

thanks in advance.

Answer 1

[Himanshu Rai]

Use this

X = reshape(X', [75, 1])

[Prakhar Modi]

thanx for the reply

but for this X should contain all 3 columns and 25 rows. but i have three different variable for three columns.

[Himanshu Rai]

Suppose a, b, c are your columns, then define X as follows and use the expression above

X = [a b c]

[Prakhar Modi]

the order of the rows are same. i want that the it should be arranged as the that the 1st 2nd and 3rd value of the column should the 1st value of all the three column

[Himanshu Rai]

Don't get what you are trying to say.

[Prakhar Modi]

for ex: col1=[1,2,3,4]

col2=[5,6,7,8]

col3=[9,10,11,12]

now i want a single column like this

output=[1,5,9,2,6,10,3,7,11,4,8,12]

[Himanshu Rai]

This is what the code does, except all the inputs and results are (according to your question) column vectors instead of row vectors

[Prakhar Modi]

t,,he answer it gives is,,

,output=[1,2,3,4,5,6,7,8,9,10,11,12]

where as i need this

output=[1,5,9,2,6,10,3,7,11,4,8,12]

[Himanshu Rai]

As I said the vectors should be column vectors and not row vectors (as you mentioned in the question).

PS - Also, verify what you write properly before commenting unnecessarily.

a = [1,2,3,4]'
b = [5,6,7,8]'
c = [9,10,11,12]'
X = [a b c]
X = reshape(X', [12, 1]) % here 12 because finally there would be 12 elements 

[Prakhar Modi]

thanks. But after some operations again want to regenrate a b c from x in same order.

[Himanshu Rai]

Use this (here X is the new modified matrix after the above operations)

X = reshape(X, [3, 25]);
X = X';
a = X(:, 1);
b = X(:, 2);
c = X(:, 3);

[Prakhar Modi]

thanx a lot

Answer 2

[Stephan]

Works also if the number of lines or columns is different to 25x3:

a = [col1 col2 col3]
b = reshape(a',[],1)

[Prakhar Modi]

thanx for the reply

but for this a should contain all 3 columns and 25 rows. but i have three different variable for three columns.

[Stephan]

see my edited answer

[Prakhar Modi]

its just giving me the same order i want to arrange it so that the new column 1st three values should be the 1st value of old three matrix

Answer 3

[Pullak Barik]

I will proceed in the following way-

1) Merge col_1, col_2, col_3 into a single matrix.

2) Reshape the transpose of the array.

The following code does the same-

res = reshape([col_1 col_2 col_3].', [], 1)

[Prakhar Modi]

its just giving me the same order i want to arrange it so that the new column 1st three values should be the 1st values of old three matrix

[Pullak Barik]

Are your col_1, col_2 and col_3 variables stored as column vectors or row vectors?