# subscat¶

## Purpose¶

Changes the values in a vector depending on the category a particular element falls in.

## Format¶

y = subscat(x, breaks, levels)
Parameters: x (Nx1 vector) – data breaks (Px1 numeric vector) – contains breakpoints specifying the ranges within which substitution is to be made. This MUST be sorted in ascending order. breaks can contain a missing value as a separate category if the missing value is the first element in breaks. If breaks is a scalar, all matches must be exact for a substitution to be made. levels (Px1 vector) – contains values to be substituted. y (Nx1 vector) – the elements in levels substituted for the original elements of x according to which of the regions the elements of x fall into: x ≤ breaks → levels breaks < x ≤ breaks → levels ... breaks[p - 1] < x ≤ breaks[p] → levels[p] x > breaks[p] → the original value of x  If missing is not a category specified in breaks, missings in x are passed through without change.

## Examples¶

### Example 1¶

// BMI Data
bmi = { 36,
19,
24,
38,
34,
16,
26,
37,
20,
34 };

// Set the breakpoints for the new categories
breaks = { 18.5, 25, 30, 40 };

// The categorical levels
levels = { 0, 1, 2, 3 };

bmi_levels = subscat(bmi, breaks, levels);


The above code assigns the following values:

bmi = 36   bmi_levels = 3
19                1
24                1
38                3
34                3
16                0
26                2
37                3
20                1
34                3


### Example 2¶

This example combines 2 levels in a categorical label into one category.

// Create categorical vector with 3 levels
x = { 1,
1,
2,
2,
1,
1,
2,
0,
2,
0 };

// Assign all instances of 2 to 1, merging the second and third categories
x = subscat(x, 2, 1);


After the code above, x is equal to:

1
1
1
1
1
1
1
0
1
0


Replacing instances of one particular value with another value can also be accomplished with reclassify() and substute()

## Remarks¶

reclassifyCuts() offers functionality similar to subscat(), but:

• Also assigns values to data past the final breakpoint.
• Offers the option of whether the breakpoints are open or closed on the right(e.g., < or ≤).
• Assigns the input to two categories in the case of a single breakpoint, (e.g., $$level\_1 < break < level\_2$$). Whereas, subscat() tests for equality in the case of a single breakpoint.