indexcat¶

Purpose¶

Returns the indices of the elements of a vector which fall into a specified category

Format¶

y = indexcat(x, v)¶

Parameters:	x (Nx1 vector) – data v (scalar or 2x1 vector) – If scalar, the function returns the indices of all elements of x equal to v. If 2x1, then the function returns the indices of all elements of x that fall into the range: \[v[1] < x <= v[2]\] If v is scalar, it can contain a single missing to specify the missing value as the category.
Returns:	y (Lx1 vector) – Indices of the elements of x which fall into the category defined by v. It will contain error code 13 if there are no elements in this category.

Examples¶

x = { 1.0, 4.0, 3.3, 4.2, 6.0, 5.7, 8.1, 5.5 };
v = { 4, 6 };
indx = indexcat(x, v);

inBds = x[indx]

       4           4.20
indx = 5   inBds = 6.00
       6           5.70
       8           5.50

Example 2: Finding rows by string value in a dataframe¶

// Create sample dataframe
sales = asdf(seqa(100, 50, 5), "sales");
region = asdf("North" $| "South" $| "North" $| "East" $| "South", "region");
df = region ~ sales;

print df;

region            sales
 North        100.00000
 South        150.00000
 North        200.00000
  East        250.00000
 South        300.00000

// Find indices of all "South" regions
south_idx = indexcat(df[., "region"], "South");

print south_idx;

2.0000000
5.0000000

// Use indices to extract matching rows
south_data = df[south_idx, .];

print south_data;

region            sales
 South        150.00000
 South        300.00000