Given a matrix, sort the rows (either in ascending or descending order) based on the values of column (column index given as an input to the function).

[chichra]

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[chichra]

@pbiswas101 Similarly, this can be extended to sorting the columns of a matrix based on a row index.

For example , given matrix
M =
[[3 2 1]
[4 6 5]
[3 4 2]]

Sorting the rows by last column gives.

M =

[[3 2 1]
[3 4 2]
[4 6 5]]

[fave77]

@chichra can you be more specific on this:

sort the rows based on the values of column

I mean are you talking about just swapping two rows? and how do the sorting works? In the example you mentioned, what if the last row was [ 3 4 7 ] and how this would affect the outcome!

[viditkumar]

@pbiswas101 I suppose, she is talking about swapping the two rows. If the last row was [ 3 4 7 ], please look at the below example.

M =
[[3 2 1]
[4 6 5]
[3 4 7]]

Sorting the rows by last column gives.
M =
[[3 2 1]
[4 6 5]
[3 4 7]]

There is no swapping required in the above scenario.
If this issue is fine and gets accepted, I would like to work on it.

[sakshichahal53]

For sorting rows by a column number let say 2, we have to look upon sorting the numbers in the given column. And accordingly the rows are swapped.
Given :
M= [[1 2 10],
[4 6 5],
[2 4 7]]

Sorting rows by 1 column gives: Since numbers in first column are 3 4 3 sorted = (3 3 4), we have
A= [[1 2 10],
[2 4 7],
[4 6 5]]

Sorting rows by 2 column gives: Since numbers in second column are 2 6 4 sorted = (2 4 6), we have
B= [[1 2 10],
[2 4 7],
[4 6 5]]

Sorting rows by 3 column gives: Since numbers in third column are 10 7 5 sorted = (5 7 10), we have
C= [[4 6 5],
[2 4 7],
[1 2 10]]

@chichra I believe this is what you suppose to mean?

[chichra]

@sakshichahal53 yes absolutely, that is what I wanted.

[chichra]

@pbiswas101 as I mentioned earlier that similarly, this can be extended to sorting the columns of a matrix based on a row index.

For example , given matrix the same matrix, If i wish to sort (rather rearrange) the columns of matrix based on the values of row 1

Original matrix is
M =
[[3 2 1]
[4 6 5]
[3 4 2]]

Sorting the columns by row indices gives.

sorted matrix M(based on row 1)=
[[1 2 3]
[5 6 4]
[2 4 3]]

sorted matrix M (based on row 2)=
[[3 1 2]
[4 5 6]
[3 2 4]]

sorted matrix M (based on row 3)=
[[1 3 2]
[5 4 6]
[2 3 4]]

[Shubhayu-Das]

I have a doubt: How will this help in competitive programming?

[fave77]

@chichra will you be working on this issue?

[chichra]

@pbiswas101 yes

[fave77]

@chichra okay, how are you planning to implement this?
please provide code snippets so as to show the usage of this function in terms of a matrix a,

const a = new M.Matrix([ [3, 2, 1], [4, 6, 5], [3, 4, 2] ])

[chichra]

a.sort('row', 0)
output will be
[[1 2 3]
[5 6 4]
[2 4 3]]

a.sort('column', 0)
[[3 2 1]
[3 4 2]
[4 6 5]]

The first parameter in function signature represents if we want to sort based on row/column and the second parameter denotes the index.

[fave77]

@chichra this issue is more or less similar to issue #152 and the sorting also need to include both ascending / descending order as mentioned in the PR #169

So, the overall implementation would be:

a.sort('row', true, 0)

where 2nd and 3rd arguments are optional! If the 3rd argument is to be omitted, then the behavior of sorting would go along as mentioned in issue #152

Hence, once that issue is resolved you may start working on this one, building on top of that implementation.

[chichra]

Yes, sure.