今天实用array_diff出现的异常问题，预想的结果应该是返回 "integral_initiate"=>"0"，实际没有
先看测试代码：
$a = [
"user_name"=>"测","see_num"=>0,"integral_initiate"=>"0"
];
$b = [
"user_name"=>"测","see_num"=>0,"integral_initiate"=>10
];
$gf = array_diff($a,$b);
print_r($gf);
没有返回差异，纠结了好一阵子又查阅了文档看到这一句话才醒悟
我们简化一下数组来看，通过简化数组发现只要两个数组中间都带有0的值就不会正常效验
解决方案就是换成 array_diff_assoc 对比键名与键值
------------序言--------------
虽然上面得到了想要的结果，但是本着刨根问底的思想继续研究了 一番，查了一些资料，也翻了下源码终于找到了一个合理的解释
/* {{{ proto array array_diff(array arr1, array arr2 [, array ...])
Returns the entries of arr1 that have values which are not present in any of the others arguments. */
PHP_FUNCTION(array_diff)
{
zval *args;
int argc, i;
uint32_t num;
HashTable exclude;
zval *value;
zend_string *str, *tmp_str, *key;
zend_long idx;
zval dummy;
if (ZEND_NUM_ARGS() < 2) {
php_error_docref(NULL, E_WARNING, "at least 2 parameters are required, %d given", ZEND_NUM_ARGS());
return;
}
ZEND_PARSE_PARAMETERS_START(1, -1)
Z_PARAM_VARIADIC('+', args, argc)
ZEND_PARSE_PARAMETERS_END();
if (Z_TYPE(args[0]) != IS_ARRAY) {
php_error_docref(NULL, E_WARNING, "Expected parameter 1 to be an array, %s given", zend_zval_type_name(&args[0]));
RETURN_NULL();
}
num = zend_hash_num_elements(Z_ARRVAL(args[0]));
if (num == 0) {
for (i = 1; i < argc; i++) {
if (Z_TYPE(args[i]) != IS_ARRAY) {
php_error_docref(NULL, E_WARNING, "Expected parameter %d to be an array, %s given", i + 1, zend_zval_type_name(&args[i]));
RETURN_NULL();
}
}
RETURN_EMPTY_ARRAY();
} else if (num == 1) {
int found = 0;
zend_string *search_str, *tmp_search_str;
value = NULL;
ZEND_HASH_FOREACH_VAL_IND(Z_ARRVAL(args[0]), value) {
break;
} ZEND_HASH_FOREACH_END();
if (!value) {
for (i = 1; i < argc; i++) {
if (Z_TYPE(args[i]) != IS_ARRAY) {
php_error_docref(NULL, E_WARNING, "Expected parameter %d to be an array, %s given", i + 1, zend_zval_type_name(&args[i]));
RETURN_NULL();
}
}
RETURN_EMPTY_ARRAY();
}
search_str = zval_get_tmp_string(value, &tmp_search_str);
for (i = 1; i < argc; i++) {
if (Z_TYPE(args[i]) != IS_ARRAY) {
php_error_docref(NULL, E_WARNING, "Expected parameter %d to be an array, %s given", i + 1, zend_zval_type_name(&args[i]));
RETURN_NULL();
}
if (!found) {
ZEND_HASH_FOREACH_VAL_IND(Z_ARRVAL(args[i]), value) {
str = zval_get_tmp_string(value, &tmp_str);
if (zend_string_equals(search_str, str)) {
zend_tmp_string_release(tmp_str);
found = 1;
break;
}
zend_tmp_string_release(tmp_str);
} ZEND_HASH_FOREACH_END();
}
}
zend_tmp_string_release(tmp_search_str);
if (found) {
RETVAL_EMPTY_ARRAY();
} else {
ZVAL_COPY(return_value, &args[0]);
}
return;
}
/* count number of elements */
num = 0;
for (i = 1; i < argc; i++) {
if (Z_TYPE(args[i]) != IS_ARRAY) {
php_error_docref(NULL, E_WARNING, "Expected parameter %d to be an array, %s given", i + 1, zend_zval_type_name(&args[i]));
RETURN_NULL();
}
num += zend_hash_num_elements(Z_ARRVAL(args[i]));
}
if (num == 0) {
ZVAL_COPY(return_value, &args[0]);
return;
}
ZVAL_NULL(&dummy);
/* create exclude map */
zend_hash_init(&exclude, num, NULL, NULL, 0);
for (i = 1; i < argc; i++) {
ZEND_HASH_FOREACH_VAL_IND(Z_ARRVAL(args[i]), value) {
str = zval_get_tmp_string(value, &tmp_str);
zend_hash_add(&exclude, str, &dummy);
zend_tmp_string_release(tmp_str);
} ZEND_HASH_FOREACH_END();
}
/* copy all elements of first array that are not in exclude set */
array_init_size(return_value, zend_hash_num_elements(Z_ARRVAL(args[0])));
ZEND_HASH_FOREACH_KEY_VAL_IND(Z_ARRVAL(args[0]), idx, key, value) {
str = zval_get_tmp_string(value, &tmp_str);
if (!zend_hash_exists(&exclude, str)) {
if (key) {
value = zend_hash_add_new(Z_ARRVAL_P(return_value), key, value);
} else {
value = zend_hash_index_add_new(Z_ARRVAL_P(return_value), idx, value);
}
zval_add_ref(value);
}
zend_tmp_string_release(tmp_str);
} ZEND_HASH_FOREACH_END();
zend_hash_destroy(&exclude);
}
/* }}} */
这就可以解释为什么使用array_diff 不能得到想要的结果，因为只要第一个数组中的值在第二个数组中出现过就不算差异，所以并不是bug，反过来再去看一下文档上面英文注释是这样写的
我只能说这个中文版的翻译有待提升，至此问题就到这里了
相关文档：
1、问题解答： https://stackoverflow.com/questions/4742405/array-diff-to-compare-two-associative-arrays/4742438#4742438 2、PHP 如何查看php函数源码-CSDN博客文章来源：https://www.toymoban.com/news/detail-807388.html
3、源码地址 ：GitCode - 开发者的代码家园 文章来源地址https://www.toymoban.com/news/detail-807388.html
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