51st Day Class regular expressions and arrays

Common methods of regular expressions:

#preg_replace (Regular expression, "X", $STR) replaces the regular expression in the string with the X-

#preg_spilt (regular expression, $str) separates the string from where it satisfies the regular expression, returning the array

#preg_match (regular expression, $STR, array) extracts the first of the string Str that satisfies the regular expression into the array

#preg_match_all (regular expression, $STR, array) extracts all the regular expressions in the string str into the array

Array

#索引数组Definition: statement definition $a =array (1,2,3,4 ...) Assignment definition $a [0]=1; $a [1]=2;

#关联数组 definition: $a =array ("One" =>5, "one" =>6 ...)

#特点: Can store any type of data, the length of the array can be changed

#for循环遍历数组: cannot traverse associative array

$a=array(1,2,3,4);  for ($i= 0; $i<count($a); $i+ +)    {echo$a[$i]. " <br> ";}

#foreach遍历数组: You can traverse associative arrays

$a=array(1,2,3,4); foreach ($aas$t) {    echo$t. <br> ";}

#foreach遍历数组: can get array element designator and value

$a=array("A" =>1, "B" =>2, "C" =>3, "D" =>4); foreach ($aas$i= +$j)    {echo$i. " =". $j. " <br> ";}

#var_dump (each ($a)); Var_dump (each ($a)); ...//Returns the code and value of the element inside the array, each time it is executed, takes an element, executes the second, and the second element ...

#list函数, the special function that appears to the left of the equals sign

List ($a, $b, $c, $d ...) = array//assigns the value inside the array to the variable in parentheses, the number of variables in parentheses must <= the number of array elements

#each, the LIS function is combined to iterate through the array.

$a=array("A" =>1, "B" =>2, "C" =>3, "D" =>4);  while (list($i,$j) =each ($a)) {    echo$i ." =". $j. " <br> ";}

#current (array)//Take the current (value) of the array element

#key (array)//take an array of elements of key (codename)

#next (array)//add pointer to one

#prey (array)//reduce the pointer by one

#end (array)//point pointer to last

#reast (array)//Reset the pointer

#用指针遍历数组

$a=array("A" =>1, "B" =>2, "C" =>3, "D" =>4);  Do {    echocurrent ($a). " =". Key ($a). " <br> ";}  while (next($a))

#获取表单数据 $_post &_get (address bar can be seen, there is a length limit)

About functions of arrays

#判断数组是否存在某个值 In_array ("element", array)

#翻转数组并返回数组 Array_reverse (Array)

#返回数组的长度 count (Array)

#去掉重复元素的索引和值 Array_unique (Array)//execute to rearrange arrays

#删除数组元素的索引和值 unset (array [x])//execute to rearrange the array

#重新排列去重的数组索引 Array_value (Array)

#合并数组 Array_merge (arrays, arrays ...)

#往数组里面追加元素 Array_push (array, Element)//new element added at the end

#定义二维数组 $a =array (array (), array (), array (), array (), array (), array (), Array () ... )

51st Day Class regular expressions and arrays