This article mainly introduces the description of string functions in PHP, which has certain reference value. Now I share it with everyone. Friends in need can refer to it
PHP String Function
strlen()Get the length
echo strlen("hello world"); output 12
substr(); Returns a part of the string.
echo substr("Hello world",6)."
"; Output world
echo substr("Hello world ",-4)."
"; Output orld
echo substr("Hello world",6,6)."
"; Output world
echo substr("Hello world",0,-6)."
"; Output Hello
substr_count(); Count the number of occurrences of a substring in a string.
substr_replace();Replace part of the string with another string.
explode()Break the string into an array:
$str = "hello world. I love Shanghai!";print_r(explode(" ",$str));
trim()
Shift Except whitespace and other characters on both sides of the string.
$str = "Hello World!";##echo trim($str,"Hed!");
ltrim()
Remove whitespace characters or other characters on the left side of the string. rtrim()
Remove whitespace characters or other characters on the right side of the string.
str_split()Split the string into an array.
print_r(str_split("Shanghai",3));
Output: Array ( [0] => Sha [1] => ngh [2] => ai )
##str_replace()Replace the string "Hello world!" in "world" replace with "Shanghai": echo str_replace("world","Shanghai","Hello world!");
##strrev()Reverse the string.
count()The function is used to return the length of the array (number of elements):
strpos()Get the search location
echo strpos("hello world!","world") output 6
strtoupper()Convert the string to
lowercase letters. strtolower() Converts a string to
uppercase letters. strip_tags() Strip HTML and PHP tags from strings
str_word_count() Count the number of words in a string.
strstr()Find the first occurrence of
(for size) of a string in another string write sensitive). stristr()Finds the first occurrence of a string in another string (not case sensitive).
echo strstr("I love Shanghai!","Shanghai"); 函数搜索字符串在另一字符串中的第一次出现。
strtr()转换字符串中特定的字符。
把字符串中的字符 "ia" 替换为 "eo":
echo strtr("Hilla Warld","ia","eo"); 输出 Hello World
strripos() 查找字符串在另一字符串中最后一次出现的位置
strrpos() 查找字符串在另一字符串中最后一次出现的位置(对大小写敏感)。
strspn();返回在字符串中包含的特定字符的数目。
echo strspn("abcdefand","abc"); 输出 3
is_array() ;判断是否是数字;
存取和修改字符串中的字符
字符串中的字符可以通过一个以0为开始的,用类似数组结构中的方括号包含对应的数字来查找和修改,比如 $str[42] , $str{42}, 可以把 字符串想像数组
$str = 'abcdefghigk'; for($i = 0;$i ';或者echo $str{$i}.'<br>'; }die // 正则校验特殊符号 $word = $f.$h.$o.$n; if(preg_match("/[\'.,:;*?~`!@ #$%^&+=)({}]|\]|\[|\/|\\\|\"|\|/",$word)){ //不允许特殊字符 }
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