NeoPixel setPixelColor works only in for loop I am working with a NeoPixel RGB led and have gone through various tutorials but I have a question regarding the setPixelColor(). 

If I do not have my setPixelColor() and show() inside of a for loop it will not work.

This works:

void holoLight(uint32_t c){
  for(uint16_t i = 0; i&lt;2; i++){
    holo_pxl.setPixelColor(i, c);
    holo_pxl.show();
    delay(2500);
  }
}


This does not:

void holoLight(uint32_t c){
    holo_pxl.setPixelColor(1, c);
    holo_pxl.show();
    delay(2500);
}


I am sure it is something specific to the language or execution but would love some clarifications, thanks =)
I am not sure I fully understand your exact problem but you have to be aware that holo_pxl.setPixelColor(1, c); set the color of the second LED in a NeoPixel chain, NOT the first one.

For the first LED, you have to use holo_pxl.setPixelColor(0, c); instead.