For

For[start,test,incr,body]

executes start, then repeatedly evaluates body and incr until test fails to give True.

Details

For evaluates its arguments in a nonstandard way.
For[start,test,incr] does the loop with a null body.
The sequence of evaluation is test, body, incr. For exits as soon as test fails.
If Break[] is generated in the evaluation of body, the For loop exits.
Continue[] exits the evaluation of body, and continues the loop by evaluating incr.
Unless an explicit Return is used, the value returned by For is Null.
Note that in an example like For[tot=0;i=0,i<3,i++,tot+=f[i]] the roles of the semicolon and comma are reversed relative to C-like programming languages.

Examples

open allclose all

Basic Examples (2)

A comma delimits the parts of For; a semicolon delimits the parts of procedures:

Scope (2)

Break breaks out of For:

Continue continues the loop without executing the rest of the body:

Properties & Relations (1)

A Do loop can be written as a For loop:

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