I have a matrix with columns containing 0s and 1s, and I want to concatenate the values in each row to create a new column in that matrix with that concatenated string.
I used
apply(format(matrix), 1, paste, collapse="")
from Concatenating N columns of text in R to create a list of concatenated values, but am having trouble getting those values into a new column in the matrix - the second line of this code has the wrong syntax.
my current code:
newcolumn <- rep(0,times=nrow(matrix))
newcolumn[matrix[apply(format(matrix), 1, paste, collapse="")]]
matrix <- cbind(matrix, newcolumn)
At the moment, you have created a vector of 0
's as newcolumn
. Your second line of code is garbage (as you rightly noted) -- see point 1.
You can cbind the results of apply(format(matrix), 1, paste, collapse="")
to matrix
. There is no need for preallocating newcolumn
.
Note that a matrix
can only hold a single type of data (ie numeric or character etc), as such if you include a character
column then the whole matrix will be coerced to character.
# examples
# a character matrix containing the result + matrix coerced to character
charResults <- cbind(matrix, apply(format(matrix), 1, paste, collapse="") )
# you could use a data.frame to have different data classes in the same structure
dfResults <- cbind(as.data.frame(matrix), result = apply(format(matrix), 1, paste, collapse=""))
Also note, it is usually good practice not to name your objects the names of base
R functions (such as matrix
)
cbind(matrix, paste0(as.character(matrix[,1]), as.character(matrix[,2])))
should do the trick. The matrix must be converted to character format to accommodate '01' cases.
Suppose that you have a Matrix A like the following;
A = [[1,2,3,4,5,6],
[11,12,13,14,15,16],
[21,22,23,24,25,26],
[31,32,33,34,35,36],
[41,42,43,44,45,46]]
You want to concatenate 1, 2, 3 columns with the 6.last column for constructing a new matrix as the following; NewA =
[[1, 2, 3, 6],
[11,12,13,16],
[21,22,23,26],
[31,32,33,36],
[41,42,43,46]]
I have found the simplest solution of achieving it as;
import numpy as np
NewA=np.concatenate((np.transpose(A)[0:3],np.transpose(A)[5:6])).transpose()
I wish it is helpful to you...
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