$arr_A_Z_a_z_0_9 = array_merge(range('A', 'Z'), range('a', 'z'), range(0, 9));
print_r($arr_A_Z_a_z_0_9);
/*
run:
Array
(
[0] => A
[1] => B
[2] => C
[3] => D
[4] => E
[5] => F
[6] => G
[7] => H
[8] => I
[9] => J
[10] => K
[11] => L
[12] => M
[13] => N
[14] => O
[15] => P
[16] => Q
[17] => R
[18] => S
[19] => T
[20] => U
[21] => V
[22] => W
[23] => X
[24] => Y
[25] => Z
[26] => a
[27] => b
[28] => c
[29] => d
[30] => e
[31] => f
[32] => g
[33] => h
[34] => i
[35] => j
[36] => k
[37] => l
[38] => m
[39] => n
[40] => o
[41] => p
[42] => q
[43] => r
[44] => s
[45] => t
[46] => u
[47] => v
[48] => w
[49] => x
[50] => y
[51] => z
[52] => 0
[53] => 1
[54] => 2
[55] => 3
[56] => 4
[57] => 5
[58] => 6
[59] => 7
[60] => 8
[61] => 9
)
*/
