How would I refactor this code, given how similar most of the lines are? I have a set of buttons and a set of NeoPixel LEDs. There's lots of very similar constants (button1pin, button2pin, etc) so there's almost certainly a more efficient way of coding this.

Any ideas?

#include &lt;Adafruit_NeoPixel.h&gt;
Adafruit_NeoPixel strip = Adafruit_NeoPixel(9, 2, NEO_RGBW + NEO_KHZ800);

// Buttons
const int button1pin = 3;
const int button2pin = 4;
const int button3pin = 5;
const int button4pin = 6;
const int button5pin = 7;
const int button6pin = 8;
const int button7pin = 9;
const int button8pin = 10;
const int button9pin = 11;

const int led1 = 0;
const int led2 = 1;
const int led3 = 2;
const int led4 = 3;
const int led5 = 4;
const int led6 = 5;
const int led7 = 6;
const int led8 = 7;
const int led9 = 8;

void setup() {
  strip.begin();
  strip.show();

  pinMode(button1pin, INPUT_PULLUP);
  pinMode(button2pin, INPUT_PULLUP);
  pinMode(button3pin, INPUT_PULLUP);
  pinMode(button4pin, INPUT_PULLUP);
  pinMode(button5pin, INPUT_PULLUP);
  pinMode(button6pin, INPUT_PULLUP);
  pinMode(button7pin, INPUT_PULLUP);
  pinMode(button8pin, INPUT_PULLUP);
  pinMode(button9pin, INPUT_PULLUP);
}

void loop() {
  if (digitalRead(button1pin) == LOW){
    strip.setPixelColor(led1, strip.Color(20, 55, 0, 0));
  }
  if (digitalRead(button2pin) == LOW){
    strip.setPixelColor(led2, strip.Color(20, 55, 0, 0));
  }
  if (digitalRead(button3pin) == LOW){
    strip.setPixelColor(led3, strip.Color(20, 55, 0, 0));
  }
  if (digitalRead(button4pin) == LOW){
    strip.setPixelColor(led4, strip.Color(20, 55, 0, 0));
  }
  if (digitalRead(button5pin) == LOW){
    strip.setPixelColor(led5, strip.Color(20, 55, 0, 0));
  }
  if (digitalRead(button6pin) == LOW){
    strip.setPixelColor(led6, strip.Color(20, 55, 0, 0));
  }
  if (digitalRead(button7pin) == LOW){
    strip.setPixelColor(led7, strip.Color(20, 55, 0, 0));
  }
  if (digitalRead(button8pin) == LOW){
    strip.setPixelColor(led8, strip.Color(20, 55, 0, 0));
  }
  if (digitalRead(button9pin) == LOW){
    strip.setPixelColor(led9, strip.Color(20, 55, 0, 0));
  }

  strip.show();
}
#include &lt;Adafruit_NeoPixel.h&gt;
Adafruit_NeoPixel strip = Adafruit_NeoPixel(9, 2, NEO_RGBW + NEO_KHZ800);
// The maximum pin number for the buttons
const int MaxButton = 11;
// The value if the pin is not connected to an LED
const int NotConnected = -1;
// The connections from buttons to leds.
const int Connections[MaxButton+1] = {NotConnected, NotConnected, NotConnected, 0, 1, 2, 3, 4, 5, 6, 7, 8};

void setup()
{
  strip.begin();
  strip.show();
  for (int pinNumber = 0; pinNumber &lt;= MaxButton; ++pinNumber)
  {
    if (Connections[pinNumber] != NotConnected)
    {
        pinMode(pinNumber, INPUT_PULLUP);
    }
  }
}

void loop()
{
  for (int pinNumber = 0; pinNumber &lt;= MaxButton; ++pinNumber)
  {
    if (Connections[pinNumber] != NotConnected)
    {
        if (digitalRead(pinNumber) == LOW)
        {
            strip.setPixelColor(Connections[pinNumber], strip.Color(20, 55, 0, 0));
        }
    }
  }
  strip.show();
}


I can't test it, so I have no idea if it works, but it should do.