Summary of use examples of array processing functions in PHP

Source: Internet
Author: User
Summary of use examples of array processing functions in PHP

  1. # Changing the case sensitivity of the array key
  2. $ Arr1 = array ("a" => "Lamp", "db" => "database", "LANGUAGE" => "PHP ");
  3. Print_r (array_change_key_case ($ arr1, CASE_UPPER ));
  4. Echo"
    ";
  5. Print_r (array_change_key_case ($ arr1, CASE_LOWER ));
  6. Echo"
    ";
  7. # Split an array into multiple third parameters to set whether to retain the key
  8. $ Arr2 = array ('A', 'B', 'C', 'D', 'e', 'F', 'g ');
  9. Print_r (array_chunk ($ arr2, 2, true ));
  10. Echo"
    ";
  11. Print_r (array_chunk ($ arr2, 2, false ));
  12. Echo"
    ";
  13. # Array array_diff_assoc (array $ array1, array $ array2 [, array $...]) returns an array,
  14. # This array includes all the values in the array of array1 but not in any other parameter array.
  15. # Different keys
  16. $ Arr3 = array ('a' => 'green', 'B' => 'brown ', 'C' => 'red ');
  17. $ Arr4 = array ('a' => 'green', 'yellow', 'red ');
  18. Print_r (array_diff_assoc ($ arr3, $ arr4 ));
  19. Echo"
    ";
  20. # Array_diff (array $ array1, array $ array2 [, array $...])
  21. # Returns an array that contains all but not any
  22. # The values in other parameter arrays are not counted if the keys are different.
  23. Print_r (array_diff ($ arr3, $ arr4 ));
  24. Echo"
    ";
  25. # Array_fill (int $ start_index, int $ num, mixed $ value)
  26. # Use the value of the value parameter to fill an array with num entries,
  27. # The key name is specified by the start_index parameter.
  28. Print_r (array_fill (-5, 8, "banana "));
  29. Echo"
    ";
  30. # Array_flip (array $ trans)
  31. # Returns an inverted array. for example, the key name in trans is changed to a value,
  32. # The value in trans is the key name.
  33. $ Arr5 = array ('a' => '1', "B" => "2", "c", "d", "e ");
  34. Print_r (array_flip ($ arr5 ));
  35. Echo"
    ";
  36. # Array_map (callback $ callback, array $ arr1 [, array $...])
  37. # Returns an array containing all the elements in arr1 that have passed the callback function
  38. # Subsequent units. The number of parameters accepted by callback should be passed to array_map ()
  39. # The number of functions is the same.
  40. Function cube ($ n ){
  41. Return $ n * $ n;
  42. }
  43. $ Arr6 = array (1, 2, 3, 4, 5 );
  44. Print_r (array_map ("cube", $ arr6 ));
  45. Echo"
    ";
  46. # Array_merge_recursive (array $ array1 [, array $...])
  47. # Merge the units of one or more arrays. the values in an array are appended to the previous array.
  48. . Returns an array of results. If the input array has the same string key name,
  49. # Then these values will be merged into an array, which will be recursive, so if a value itself
  50. # Is an array. this function combines it into another array according to the corresponding entries. However, for example
  51. # If the array has the same array key name, the next value will not overwrite the original value, but will be appended
  52. .
  53. $ Arr7 = array ("color" => array ("favorite" => "red"), 5 );
  54. $ Arr8 = array (10, array ("favorite" => "yellow", "blue "));
  55. Print_r (array_merge_recursive ($ arr7, $ arr8 ));
  56. Echo"
    ";
  57. # Array_reduce (array $ input, callback $ function [, int $ initial]
  58. # Iterate the callback function to every unit in the input array, so that the array
  59. # Simplified to a single value. If the optional parameter initial is specified, the parameter is treated as
  60. # Process a value, or use the final return value if the array is empty. If the array is empty and no
  61. # If the initial parameter is passed, array_reduce () returns NULL.
  62. Function rsum ($ v, $ w ){
  63. $ V + = $ w;
  64. Return $ v;
  65. }
  66. Function rmul ($ v, $ w ){
  67. $ V * = $ w;
  68. Return $ v;
  69. }
  70. $ A = array (1, 2, 3, 4, 5 );
  71. $ X = array ();
  72. $ B = array_reduce ($ a, "rsum ");
  73. $ C = array_reduce ($ a, "rmul", 10 );
  74. $ D = array_reduce ($ x, "rsum", 1 );
  75. Echo $ B. "\ t". $ c. "\ t". $ d. "\ n ";
  76. Echo"
    ";
  77. # Array_replace (array & $ array, array & $ array1 [, array & $ array2 [, array & $...])
  78. # The function replaces the value of the first array with the value of the following array element. If a key exists in the first
  79. # An Array also exists in the second array, and its value will be replaced by the value in the second array. If
  80. # If the key exists in the second array but does not exist in the first array, this
  81. # Element. If a key only exists in the first array, it remains unchanged. If multiple replicas are passed
  82. # Groups, which are processed sequentially, and the subsequent arrays overwrite the previous values.
  83. $ Base = array ("orange", "banana", "apple", "raspberry ");
  84. $ Replacements = array (0 => "pineapple", 4 => "cherry ");
  85. $ Replacements2 = array (0 => "grape ");
  86. # Print_r (array_replace ($ base, $ replacements, $ replacements2 ));
  87. # Echo"
    ";
  88. # Array_splice (array & $ input, int $ offset [, int $ length [, array $ replacement])
  89. # Remove the units specified by offset and length from the input array. if replacement is provided
  90. # Parameter, which is replaced by cells in the replacement array. Returns an array containing the removed cells.
  91. #. Note that the number key name in input is not retained. If length is omitted, remove
  92. # Offset all parts to the end. If length is specified and it is a positive value, so many units are removed.
  93. #. If length is specified and it is a negative value, remove the reciprocal length from offset to the end of the array.
  94. # All units in the middle. Tips: remove from offset
  95. # Count ($ input) is used as the length for all cells at the end of the array.
  96. $ Input = array ("red", "green", "blue", "yellow ");
  97. Array_splice ($ input, 1,-1 );
  98. Print_r ($ input );
  99. Echo"
    ";
  100. # Key (array & $ array)
  101. # Return the key name of the current cell in the array.
  102. $ Fruit = array ("fruit1" => "apple", "fruit2" => "orange", "fruit3" => "grape ",
  103. "Fruit4" => "apple", "fruit5" => "apple ");
  104. While ($ fruit_name = current ($ fruit )){
  105. If ($ fruit_name = 'apple '){
  106. Echo key ($ fruit )."
    ";
  107. }
  108. Next ($ fruit );
  109. }
  110. Echo"
    ";
  111. ?>


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