In PHP, array_merge merges two arrays.

In php, we use the array_merge () function to merge data. the array_merge () function combines two or more numbers into an array. If the key name already exists, the key value of the key is the value corresponding to the last key name (the subsequent one overwrites the previous one ).

In php, we use the array_merge () function to merge data. the array_merge () function combines two or more numbers into an array. if the key name already exists, the key value of the key is the value corresponding to the last key name (the latter overwrites the previous one ). if the array is a digital index, the key name is re-indexed continuously.

The instance code is as follows:

2. Echo "rn First case rn ";
3. $ A = array (1, 2, 3, 4, 5, 6 );
4. $ B = array (7,8, 9 );
6. $ C = array_merge ($ a, $ B );
7. Print_r ($ c );
8. $ C = $ a + $ B;
9. Print_r ($ c );
10. $ C = $ B + $;
11. Print_r ($ c );
14. Echo "rn second case rn ";
15. $ A = array ('A', 'B', 'C', 'D', 'e', 'F ');
16. $ B = array ('A', 'X', 'y ');
18. $ C = array_merge ($ a, $ B );
19. Print_r ($ c );
20. $ C = $ a + $ B;
21. Print_r ($ c );
22. $ C = $ B + $;
23. Print_r ($ c );
26. Echo "rn case 3 rn ";
28. $ A = array (
29. 1 => 'A ',
30. 2 => 'B ',
31. 3 => 'C ',
32. 4 => 'D ',
33. 5 => 'e ',
34. 6 => 'F ');
35. $ B = array (
36. 1 => 'A ',
37. 7 => 'X ',
38. 8 => 'y ');
40. $ C = array_merge ($ a, $ B );
41. Print_r ($ c );
42. $ C = $ a + $ B;
43. Print_r ($ c );
44. $ C = $ B + $;
45. Print_r ($ c );
46. ?>
47. The result is as follows:
48. First case
49. Array
50. (
51. [0] => 1
52. [1] => 2
53. [2] => 3
54. [3] => 4
55. [4] => 5
56. [5] => 6
57. [6] => 7
58. [7] => 8
59. [8] => 9
60. )
61. Array
62. (
63. [0] => 1
64. [1] => 2
65. [2] => 3
66. [3] => 4
67. [4] => 5
68. [5] => 6
69. )
70. Array
71. (
72. [0] => 7
73. [1] => 8
74. [2] => 9
75. [3] => 4
76. [4] => 5
77. [5] => 6
78. )
80. Case 2
81. Array
82. (
83. [0] =>
84. [1] => B
85. [2] => c
86. [3] => d
87. [4] => e
88. [5] => f
89. [6] =>
90. [7] => x
91. [8] => y
92. )
93. Array
94. (
95. [0] =>
96. [1] => B
97. [2] => c
98. [3] => d
99. [4] => e
100. [5] => f
101. )
102. Array
103. (
104. [0] =>
105. [1] => x
106. [2] => y
107. [3] => d
108. [4] => e
109. [5] => f
110. )
112. Case 3
113. Array
114. (
115. [0] =>
116. [1] => B
117. [2] => c
118. [3] => d
119. [4] => e
120. [5] => f
121. [6] =>
122. [7] => x
123. [8] => y
124. )
125. Array
126. (
127. [1] =>
128. [2] => B
129. [3] => c
130. [4] => d
131. [5] => e
132. [6] => f
133. [7] => x
134. [8] => y
135. )
136. Array
137. (
138. [1] =>
139. [7] => x
140. [8] => y
141. [2] => B
142. [3] => c
143. [4] => d
144. [5] => e
145. [6] => f
146. )

1) when the key name is a number, array_merge () will not overwrite the original value, but + merges the array and returns the first value as the final result, the values of the following arrays with the same key names are discarded (not overwritten)

2) when the key name is a character, + still returns the first value as the final result, and discards the values with the same key name in the subsequent array, but array_merge () at this time, the values with the same key names will be overwritten.

Note: If you only input an array to the array_merge () function and the key name is an integer, the function returns a new array with an integer key name, its key name starts from 0 and is re-indexed