PHP common functions
下面是我整理的PHP中常用的函数,有兴趣的小伙伴可以去看看。
array_intersect()
比较两个数组的键值,并返回交集:
<?php $a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow"); $a2=array("e"=>"red","f"=>"green","g"=>"blue");$result=array_intersect($a1,$a2); print_r($result); ?> result:Array ( [a] => red [b] => green [c] => blue )
array_keys() 函数
返回包含数组中所有键名的一个新数组。
<?php $a=array("Volvo"=>"XC90","BMW"=>"X5","Toyota"=>"Highlander"); print_r(array_keys($a)); ?> result:Array ( [0] => Volvo [1] => BMW [2] => Toyota )123456
array_key_exists() 函数
检查某个数组中是否存在指定的键名,如果键名存在则返回 true,如果键名不存在则返回 false。
<?php $a=array("Volvo"=>"XC90","BMW"=>"X5"); if (array_key_exists("Volvo",$a)) { echo "键存在!"; } else { echo "键不存在!"; }?> result:键存在!12345678910111213
array_merge() 函数
把两个数组合并为一个数组:
<?php $a1=array("red","green");$a2=array("blue","yellow"); print_r(array_merge($a1,$a2)); ?> result:Array ( [0] => red [1] => green [2] => blue [3] => yellow )1234567
array_reverse()
以相反的元素顺序返回数组:
<?php $a=array("a"=>"Volvo","b"=>"BMW","c"=>"Toyota"); print_r(array_reverse($a)); ?> result:Array ( [c] => Toyota [b] => BMW [a] => Volvo )123456
array_unshift() 函数
用于向数组插入新元素。新数组的值将被插入到数组的开头。
<?ph $a=array("a"=>"red","b"=>"green"); array_unshift($a,"blue"); print_r($a); ?> result:Array ( [0] => blue [a] => red [b] => green )1234567
array_values
返回一个包含给定数组中所有键值的数组,但不保留键名。
<?php $a=array("Name"=>"Bill","Age"=>"60","Country"=>"USA"); print_r(array_values($a)); ?> result:Array ( [0] => Bill [1] => 60 [2] => USA )123456
hash_equals
可防止时序攻击的字符串比较
比较两个字符串,无论它们是否相等,本函数的时间消耗是恒定的。
本函数可以用在需要防止时序攻击的字符串比较场景中, 例如,可以用在比较 crypt() 密码哈希值的场景。
bool hash_equals ( string $known_string , string $user_string )1
参数:
known_string
已知长度的、要参与比较的 string
user_string
用户提供的字符串
返回值:
当两个字符串相等时返回 TRUE,否则返回 FALSE。
<?php$expected = crypt('12345', '$2a$07$usesomesillystringforsalt$'); $correct = crypt('12345', '$2a$07$usesomesillystringforsalt$'); $incorrect = crypt('apple', '$2a$07$usesomesillystringforsalt$'); var_dump(hash_equals($expected, $correct)); var_dump(hash_equals($expected, $incorrect)); ?> result: bool(true) bool(false)123456789101112
in_array() 函数
搜索数组中是否存在指定的值。
<?php$people = array("Bill", "Steve", "Mark", "David");if (in_array("Mark", $people)) { echo "匹配已找到"; }else { echo "匹配未找到"; } ?> result:匹配已找到1234567891011121314
sprintf() 函数
把百分号(%)符号替换成一个作为参数进行传递的变量:
<?php $number = 2; $str = "Shanghai"; $txt = sprintf("There are %u million cars in %s.",$number,$str); echo $txt; ?> result:There are 2 million cars in Shanghai.12345678
str_ireplace()
替换字符串中的一些字符(不区分大小写) str_ireplace(find,replace,string,count)
<?php echo str_ireplace("WORLD","Shanghai","Hello world!"); ?> result:Hello Shanghai!12345
strpos
查找字符串在另一字符串中第一次出现的位置。
<?php echo strpos("You love php, I love php too!","php"); ?> result:912345
str_replace()
以其他字符替换字符串中的一些字符(区分大小写)
<?php echo str_replace("world","Shanghai","Hello world!"); ?> result:Hello Shanghai!12345
str_ireplace()
替换字符串中的一些字符(不区分大小写)
str_ireplace(find,replace,string,count)
<?php echo str_ireplace("WORLD","Shanghai","Hello world!"); ?> result:Hello Shanghai!12345
substr
返回字符串的一部分。
<?php echo substr("Hello world",6); ?> result:world
上面是我整理给大家的PHP常用函数,希望今后会对大家有帮助。
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