In ESP-12E NodeMCU, all digital pins can be called with a number. Here is the list:
static const uint8_t D0 = 16;
static const uint8_t D1 = 5;
static const uint8_t D2 = 4;
static const uint8_t D3 = 0;
static const uint8_t D4 = 2;
static const uint8_t D5 = 14;
static const uint8_t D6 = 12;
static const uint8_t D7 = 13;
static const uint8_t D8 = 15;
static const uint8_t D9 = 3;
static const uint8_t D10 = 1;
So these two lines of code will do the same:
pinMode (D0, INPUT)
pinMode (16, INPUT)
What's the corresponding number for A0 (the only analog input of this board)?