if

Arguments

expr1, expri

logical expressions

statements

blocks of valid statements.

Description

The if statement evaluates a logical expression and executes a group of statements when the expression is true.

The expri are expressions with numeric or boolean values. If expri is a non-scalar value then the condition is true only if all entries of this value are true or different from zero.

The optional elseif and else provide for the execution of alternate groups of statements. An end keyword, which matches the if, terminates the last group of statements. The line structure of if is not significant, the only constraint is that each then keyword must be on the same line as its corresponding if or elseif keyword.

The keyword then can be replaced by a carriage return or a comma.

According to the Code Conventions for the Scilab Programming Language it is recommended:

• Start each statement on a new line.

• Write no more than one simple statement per line.

• Break compound statements over multiple lines.

For example, use:

if rand(1,1) > 0.5 then
disp("True");
else
disp("False");
end

rather than

if rand(1,1) > 0.5 then disp("True"); else disp("False"); end

Warning: the number of characters used to define the body of any conditional instruction (if while for or select/case) must be limited to 16k.

Examples

i=2
for j = 1:3,
  if i == j then
    a(i,j) = 2;
  elseif abs(i-j) == 1 then
    a(i,j) = -1;
  else a(i,j) = 0;
  end,
end

See Also

• try — beginning of try block in try-catch control instruction
• while — while keyword
• select — select keyword
• boolean — Scilab Objects, boolean variables and operators & | ~
• end — end keyword
• then — keyword in control flows 'if' and 'select'
• else — keyword in if-then-else and select-case-then-else
• comparison — comparison, relational operators