if

keyword for conditional execution

Calling Sequence

if expr1 then
statements
elseif expri then
statements
....
else
statements
end

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 nonscalar 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