for

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Introduced with Armed Assault version 1.00
  

Click on the images for descriptions

Introduced in

Game:
Armed Assault
Version:
1.00

Description

Description:
This operator creates a For Type which is used in the for-constructs.
Alternative syntax for array do code is slower than the alternative because the condition is checked every iteration.

Syntax

Syntax:
for arguments
Parameters:
arguments: String - declares the index variable name like "_myVar". from and to are required, step is optional.
Return Value:
For Type

Alternative Syntax

Syntax:
for array
Parameters:
array: Array - a 3-dimensional array of Code as follow: [init, condition, codeToExecute]
Return Value:
For Type

Examples

Example 1:
for "_i" from 1 to 10 do { systemChat str _i; }; Will output 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 (the to value is inclusive)
Example 2:
for "_i" from 9 to 1 step -2 do { systemChat str _i; };
Example 3:
for [{ _i = 0 }, { _i < 10 }, { _i = _i + 1 }] do { systemChat str _i };
Example 4:
// BAD CODE _i = 100; for [{_i = 0}, {_i < 5}, {_i = _i + 1}] do {}; hint str _i; // 5 // GOOD CODE (private keyword is recommended) _i = 100; for [{private _i = 0}, {_i < 5}, {_i = _i + 1}] do {}; hint str _i; // 100

Additional Information

Multiplayer:
-
See also:
Control Structureswhiledo

Notes

Only post proven facts here. Report bugs on the feedback tracker. Use the talk page or the forums for discussions.
Add New Note | How To

Notes

Posted on 29 April 2010 (CEST)
alef
for "_i" from 0 to 0 do {}; // will do once, with _i = 0 for "_i" from 0 to -1 do {}; // will not do
Posted on Apr 15, 2014 - 12:54
ffur2007slx2_5
  • Introduced with Arma 3 version 1.16
    Please note the difference between the two syntaxed; for arguments detects Boolean in each scope while for array doesn’t. e.g.
command Structure Summary
for array
a = 0; b = true;
for [{ _i = 0 }, { _i < 10 && b }, { _i = _i + 1 }] do {
	a = a + 1; 
	if (a >= 7) then {b = false}
}
loop can be exited via Boolean control, possible workaround can be like BIS_fnc_areEqual
for arguments
a = 0;
for "_i" from 0 to 10 do {
	a = a + 1;
	if (a >= 7) exitwith {}
};
has to be exited via exitWith


  • Never try to tell a decimal number via binary number in a loop; otherwise the loop will be infinite:

for [{_a = 0},{_a != 1},{_a = _a + 0.1}] do {}; // an infinite loop; _a will never be 1 so the scope will always be true Any binary number behind the decimal point is always the sum of 1/2, 1/4, 1/8, 1/16 etc. so decimal number with odd denominator like 1/3 or 1/10 cannot be exactly equal to each other.

  • Avoid too large factorial multiply which may loose the leading indicator in result. And 12 is the biggest accessable factor in this example.

for [{_a = 2; _b = 1;},{_a < 100},{_a = _a + 1}] do {_b = _b * _a}; // _b = 1.#INF

Posted on June 4, 2015 - 19:27 (UTC)
Killzone Kid
Variable name doesn't have to start with _. could be:for "LAlala" from 0 to 0 do {hint str LAlala}; // 0 The variable LAlala will exist only inside do {} scope and will not overwrite any variable of the same name that existed before.
Posted on June 4, 2015 - 19:45 (UTC)
Nickorr
Dont use this notation if you plan to change the cycle ranges dynamically. The range values are checked only before the cycle started. Use for array instead.
Example, that won't work correctly: _xy = [1,2,3,4,5,6,7,8,9,10]; for "_i" from 0 to (count _xy - 1) do { if ( _xy select _i == 3 ) then { _xy deleteAt _i; _i = _i - 1; }; }; (Here the _i = 9 step will still be checked by the cycle, which will lead to "out of the array range" error.)
This code will work correctly: _xy = [1,2,3,4,5,6,7,8,9,10]; for [{_i=1},{_i<=(count _xy - 1)},{_i=_i+1}] do { if ( _xy select _i == 3 ) then { _xy deleteAt _i; _i = _i - 1; }; }; (The last step here will be _i = 8 with array looking like this: [1,2,4,5,6,7,8,9,10])
Posted on January 29, 2016 - 05:18 (UTC)
DreadedEntity
For loops can be safely nested. This means that there should not be any problems with recursion. _array = []; for "_i" from 0 to 3 do { for "_i" from 0 to 3 do { _array pushBack _i; }; _array pushBack _i; }; hint str _array;