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docs/reference/js/for.md

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+# For
+
+Repeat code a preset number of times. #docs #for #endfor #language
+
+### @parent js/language
+ 
+
+Repeat code a fixed number of times.
+
+### Block Editor
+
+![](/static/mb/events-0.png)
+
+The Block Editor *for* loop is different than the Touch Develop *for* loop in an important way. The above for loop will iterate *five* times, with the loop variable *i* taking on values 0, 1, 2, 3, and 4. The Touch Develop for loop shown below will iterate four times:
+
+```
+for (let k = 0; k < 4; k++) {
+}
+```
+
+### Touch Develop
+
+### ~hide
+
+```
+let upper = 5
+```
+
+### ~
+
+```
+for (let k1 = 0; k1 < upper; k1++) {
+    // Add code to repeat here, also called the `loop body`
+}
+```
+
+where
+
+* `0` is initial value of the loop index variable `k`
+* the value of `k` increases by 1 after each execution of the `loop body`
+* `upper` is the number of times the loop body will repeat
+
+In other words, the index variable (`k`) starts at 0 and increases by 1 each time the `loop body` executes, until `k = upper`.
+
+### Example: count to 5
+
+The following example displays numbers 1 through 5 on the LED screen:
+
+```
+for (let i = 0; i < 5; i++) {
+    basic.showNumber(i + 1, 100)
+    basic.pause(500)
+}
+```
+
+### Example: draw a box
+
+The [LED screen](/microbit/device/screen) has a fixed number of rows and columns (5x5), which is ideal for a for loop. This example uses a for loop to turn on the LEDs along the edge of the screen, making a square.
+
+```
+for (let i1 = 0; i1 < 5; i1++) {
+    led.plot(0, i1)
+    led.plot(4, i1)
+    led.plot(i1, 0)
+    led.plot(i1, 4)
+    basic.pause(500)
+}
+```
+
+### ~hint 
+
+Want to exit a loop early? The [break](/microbit/js/break) statement exits a loop before the end value is reached.
+
+### ~
+
+### Lessons
+
+[looper](/microbit/lessons/looper), [strobe light](/microbit/lessons/strobe-light)
+
+### See also
+
+[while](/microbit/js/while), [break](/microbit/js/break), [if](/microbit/reference/logic/if)
+