read from keypad to array

// read from keypad to array
// in this code working
// but when I use for loop it's not working properly the Key can enter to the same array several pressing.

#include <AnalogMatrixKeypad.h>
#define analogPin 0
AnalogMatrixKeypad AnMatrixKeypad(analogPin);

char Key,attempt[2];
int i=0;

void setup()
{
 Serial.begin(9600);
}

void loop()
{
 Key = AnMatrixKeypad.readKey();
 if (Key != KEY_NOT_PRESSED)
 {
  attempt[i]=Key;
  Serial.println(attempt[i]);
  i++;
 }
  if(i==2)
   i=0;
}

-----------------------------------------------------------


//for loop not working properly
for(i=0; i<2; i++)
 {
  Key = AnMatrixKeypad.readKey();
  if (Key != KEY_NOT_PRESSED)
  {
   attempt[i]=Key;
   Serial.print("The Key ");
   Serial.println(attempt[i]);
   Serial.print("enter to the array ");
   Serial.println(i);
  }
 }