Enumerable For Statement

The enumerable for statement is used to enumerate the elements of an object—any object that implements IEnumerable.


for <variable> in <expression>

The variable can be from a pre-existing variable declaration or can be a new declaration. The expression must implement System.Collections.Generic.IEnumerable<of> or System.Collections.IEnumerable. Some of the more common objects to enumerate are lists, arrays and variable arguments.

If the variable is given an explicit type (foo as Bar), or has one due to being a pre-existing variable, then the type must be compatible with the objects being enumerated. If there is no explicit type then the type is inferred from what is being enumerated. For IEnumerable<of>, that's the type argument to the generic. For IEnumerable, the inferred type is Object.

Within the statements the variable can be assigned to.

Inside the statements, a break statement will exit the loop and a continue statement will skip the remaining statements. In either case, an if statement is used to control when the loop is broken or continued (otherwise it would be pointless to have further statements in the loop).

# Example 1
for person in people
    print person

# Example 2
i = 1
for person in people
    print '[i]. [person]'
    i += 1

# Example 3
for line as String in lines
    line = line.trim
    if line
        print line

# Example 4
for node in nodes
    if not node.isActive
        print 'skipping inactive node: [node]'
    print node

# Example 5
found = false
for cust in customers
    if == name
        found = true