delcols#
Purpose#
Returns a matrix with specified columns removed.
Format#
- x_trim = delcols(x, c_idx)#
- Parameters:
x (Matrix or dataframe)
c_idx (Scalar, string or vector) – index of columns to remove from x. These may be integers or variable names of a dataframe. Negative integers will start from the back. For example, -1 will indicate to remove the final column of x.
- Returns:
x_trim (matrix) – equal to input x without columns specified by input c_idx. If no columns remain, x_trim will be an empty matrix.
Examples#
Example 1: Basic matrix usage#
x = { 1 2 3 4,
5 6 7 8,
9 10 11 12 };
// Remove the second column of 'x'
x_trim = delcols(x, 2);
After the above code:
1 3 4
x_trim = 5 7 8
9 11 12
Example 2: Remove two columns from a matrix#
x = { 1 2 3 4,
5 6 7 8,
9 10 11 12 };
// Remove the second and fourth columns of 'x'
c_idx = { 2, 4 };
x_trim = delcols(x, c_idx);
After the above code:
1 3
x_trim = 5 7
9 11
Example 3: Negative index example#
x = { 1 2 3 4,
5 6 7 8,
9 10 11 12 };
// Remove the final column of 'x'
x_trim = delcols(x, -1);
After the above code:
1 2 3
x_trim = 5 6 7
9 10 11
Example 4: Dataframe#
// Load three variables into a dataframe
fname = getGAUSSHome("examples/detroit.dta");
detroit = loadd(fname, "ft_police + unemployment + hourly_earn");
// Print the first three observations
print detroit[1:3,.];
will return the following output:
ft_police unemployment hourly_earn
260.35000 11.000000 2.9800000
269.80000 7.0000000 3.0900000
272.04000 5.2000000 3.2300000
// Remove the variable 'ft_police'
detroit = delcols(detroit, "ft_police");
// Print the first three observations
// after removing the variable
print detroit[1:3,.];
unemployment hourly_earn
11.000000 2.9800000
7.0000000 3.0900000
5.2000000 3.2300000