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A brief discussion of PHP source code 11: Introduction to array_key_exists, in_array
A brief discussion of PHP source code 11: Introduction to array_key_exists, in_array
This article mainly introduces the brief discussion on PHP source code 11: the introduction of array_key_exists and in_array, which has certain reference value. Now I share it with you. Friends in need can refer to it.
Brief Discussion PHP source code 11: Introduction to array_key_exists, in_array
array_key_exists
(PHP 4 >= 4.1.0, PHP 5)
array_key_exists — Check the given key name or index Whether it exists in the array
Description
bool array_key_exists (mixed key, array search)
array_key_exists() Returns TRUE when the given key exists in the array. key can be any value that can be used as an array index. array_key_exists() also works with objects.
The program will process three different types separately,
1. String: case IS_STRING:
==> static inline int zend_symtable_exists(HashTable *ht, char *arKey, uint nKeyLength )
==>#define HANDLE_NUMERIC(key, length, func) // Will process the string type key value, if it is a number, take the value obtained by the func value, otherwise go to the next step
==> ; ZEND_API int zend_hash_exists(HashTable *ht, char *arKey, uint nKeyLength) // Determine whether this string exists in the hashtable where the array is located
2. Number: case IS_LONG:
==>ZEND_API int zend_hash_index_exists (HashTable *ht, ulong h) // This function takes the bucket with index value h. If there are multiple values in this index, it traverses and takes the bucket whose key value is numeric.
3. Word value: case IS_NULL:
==>zend_hash_exists(HASH_OF(*array), "", 1) // Determine whether there is a null value in the hashtable where the array is located.
If the above function exists like this: RETURN_TRUE; otherwise: RETURN_FALSE;
in_array
(PHP 4, PHP 5)
in_array — Check whether a certain value exists in the array
Description
bool in_array (mixed needle, array haystack [, bool strict] )
Search for needle in haystack and return TRUE if found, otherwise return FALSE.
If the value of the third parameter strict is TRUE, the in_array() function will also check whether the type of needle is the same as that in haystack.
Note: If needle is a string, the comparison is case-sensitive.
Note: Before PHP version 4.2.0, needle was not allowed to be an array.
The program implementation is very simple, traverse the hash table where the array is located, select the comparison function based on strict, if it is true, use is_identical_function, otherwise is_equal_function, the default value of strict is FALSE
Then use this function to determine whether Equal, if it exists, it will return TRUE directly
But in the program we see target_hash = HASH_OF(*array);
The macro source code is as follows:
#define HASH_OF(p) (Z_TYPE_P(p)==IS_ARRAY ? Z_ARRVAL_P(p) : ((Z_TYPE_P(p)==IS_OBJECT ? Z_OBJ_HT_P(p)->get_properties((p) TSRMLS_CC) : NULL)))
The function of this method is to judge Whether it is an array, if it is an array, return an array, otherwise determine whether it is an object, if it is an object, return all properties of the object, otherwise return NULL
But there is also a judgment in front of whether the parameter is an array, the following code:
if (Z_TYPE_PP(array) != IS_ARRAY) {
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Wrong datatype for second argument");
RETURN_FALSE;
}Is it a problem left over from history?
strangeness!
EOF
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Related recommendations:
A brief discussion on PHP source code ten: About array_keys, array_values function
A brief discussion on PHP source code nine: About array_unshift, Introduction to array_push
A brief discussion of PHP source code 8: Introduction to array_pop, array_shift
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