creating a new column with three columns

2019 6 25
3 个回答
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更新时间：2019 6 25
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0 个投票

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.

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 采纳的回答

Himanshu Rai
Himanshu Rai 2019-6-25

0 个投票

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

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Prakhar Modi
Prakhar Modi 2019-6-25
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
Himanshu Rai 2019-6-25
Suppose a, b, c are your columns, then define X as follows and use the expression above
X = [a b c]
Prakhar Modi
Prakhar Modi 2019-6-25
编辑：Prakhar Modi 2019-6-25
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
Himanshu Rai 2019-6-25
Don't get what you are trying to say.
Prakhar Modi
Prakhar Modi 2019-6-25
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
Himanshu Rai 2019-6-25
编辑：Himanshu Rai 2019-6-25
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
Prakhar Modi 2019-6-25
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
Himanshu Rai 2019-6-25
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
Prakhar Modi 2019-6-25
thanks. But after some operations again want to regenrate a b c from x in same order.
Himanshu Rai
Himanshu Rai 2019-6-25
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);

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更多回答（2 个）

Stephan
Stephan 2019-6-25
编辑：Stephan 2019-6-25

0 个投票

Works also if the number of lines or columns is different to 25x3:
a = [col1 col2 col3]
b = reshape(a',[],1)

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Prakhar Modi
Prakhar Modi 2019-6-25
编辑：Prakhar Modi 2019-6-25
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
Stephan 2019-6-25
see my edited answer
Prakhar Modi
Prakhar Modi 2019-6-25
编辑：Prakhar Modi 2019-6-25
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

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Pullak Barik
Pullak Barik 2019-6-25
编辑：Pullak Barik 2019-6-25

0 个投票

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)

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Prakhar Modi
Prakhar Modi 2019-6-25
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
Pullak Barik 2019-6-25
Are your col_1, col_2 and col_3 variables stored as column vectors or row vectors?

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