elseif (MATLAB Functions)

Conditionally execute statements

Syntax

if expression1
    statements1
elseif expression2
    statements2
end

Description

If expression1 evaluates as false and expression2 as true, MATLAB executes the one or more commands denoted here as statements2.

A true expression has either a logical 1 (true) or nonzero value. For nonscalar expressions, (for example, is matrix A less then matrix B), true means that every element of the resulting matrix has a true or nonzero value.

Expressions usually involve relational operations such as (count < limit) or isreal(A). Simple expressions can be combined by logical operators (&,|,~) into compound expressions such as (count < limit) & ((height - offset) >= 0).

See if for more information.

Remarks

else if, with a space between the else and the if, differs from elseif, with no space. The former introduces a new, nested if, which must have a matching end. The latter is used in a linear sequence of conditional statements with only one terminating end.

The two segments shown below produce identical results. Exactly one of the four assignments to x is executed, depending upon the values of the three logical expressions, A, B, and C.

if A                           if A
   x = a                           x = a
else                           elseif B
   if B                            x = b
      x = b                    elseif C
   else                            x = c
       if C                    else
          x = c                    x = d
       else                    end
           x = d
       end
   end
end

Examples

Here is an example showing if, else, and elseif.

for m = 1:k
    for n = 1:k
        if m == n
            a(m,n) = 2;
        elseif abs(m-n) == 2
            a(m,n) = 1;
        else
            a(m,n) = 0;
        end
    end
end

For k=5 you get the matrix

a =

     2     0     1     0     0
     0     2     0     1     0
     1     0     2     0     1
     0     1     0     2     0
     0     0     1     0     2

See Also

if, else, end, for, while, switch, break, return, relational operators, logical operators (elementwise and short-circuit)

else end