## Combining Unlike Integer Types

### Overview

If you combine different integer types in a matrix (e.g., signed with unsigned, or 8-bit
integers with 16-bit integers), MATLAB^{®} returns a matrix in which all elements are of one common type. MATLAB sets all elements of the resulting matrix to the data type of the leftmost
element in the input matrix. For example, the result of the following concatenation is a
vector of three 16-bit signed integers:

A = [int16(450) uint8(250) int32(1000000)]

A = 1×3 int16 row vector 450 250 32767

### Example of Combining Unlike Integer Sizes

Concatenate the following two numbers once, and then switch their order. The return value depends on the order in which the integers are concatenated. The leftmost type determines the data type for all elements in the vector:

A = [int16(5000) int8(50)]

A = 1×2 int16 row vector 5000 50

B = [int8(50) int16(5000)]

B = 1×2 int8 row vector 50 127

The first operation returns a vector of 16-bit integers. The
second returns a vector of 8-bit integers. The element `int16(5000)`

is
set to `127`

, the maximum value for an 8-bit signed
integer.

The same rules apply to vertical concatenation:

C = [int8(50); int16(5000)]

C = 2×1 int8 column vector 50 127

### Example of Combining Signed with Unsigned

Now do the same exercise with signed and unsigned integers. Again, the leftmost element determines the data type for all elements in the resulting matrix:

A = [int8(-100) uint8(100)]

A = 1×2 int8 row vector -100 100

B = [uint8(100) int8(-100)]

B = 1×2 uint8 row vector 100 0

The element `int8(-100)`

is set to zero because
it is no longer signed.

MATLAB evaluates each element *prior to* concatenating
them into a combined array. In other words, the following statement
evaluates to an 8-bit signed integer (equal to 50) and an 8-bit unsigned
integer (unsigned -50 is set to zero) before the two elements are
combined. Following the concatenation, the second element retains
its zero value but takes on the unsigned `int8`

type:

A = [int8(50), uint8(-50)]

A = 1×2 int8 row vector 50 0