add examples/set_range.py

examples/set_range.py

@@ -0,0 +1,40 @@
+# Example showing use of 'slice setting'
+import time
+from neopixel import Neopixel
+
+
+numpix = 60
+K = 3
+
+strip = Neopixel(numpix, 0, 0, "GRB")
+red = (255, 0, 0)
+green = (0, 255, 0)
+blue = (0, 0, 255)
+
+# set the first K to red, next K to green, next K to blue;
+# and the rest to R,G,B,R,B  ... and then spin it.
+
+# reduce K, if numpix is < K*3+1
+K = min(K,(numpix-1)//3)
+
+strip.brightness(80)
+
+strip[:] = blue   # all to blue first...
+# now fill in the red & green...
+strip[:K] = red
+strip[K:2*K] = green
+strip[3*K::3] = red
+strip[3*K+1::3] = green
+
+strip.show()
+
+# show it for 5 seconds...
+time.sleep(5.0)
+
+# spin it...
+
+while(True):
+    strip.rotate_right()
+    strip.show()
+    time.sleep(0.5)
+