PHP編程中字符串處理的5個技巧
PHP編程中字符串處理的5個技巧你了解多少呢？就跟隨百分網小編一起去了解下吧，想了解更多相關信息請持續關注我們應屆畢業生考試網!
字符串
注意單引號和雙引號的區別
注意轉義字符\的使用\\,\",\$
注意使用8進制或16進制字符表示 \xf6
echo "H\xf6me";/pic/p>
---------------------輸出結果----------------------------------------
H鰉e
---------------------------------------------------------------------
1.使用printf()和sprintf()創建格式化的輸出
printf()直接輸出到輸出緩沖區
sprintf()的輸出作為字符串返回
如printf("輸出內容 %.2f\n",$PI());
所有的轉換規范都以%開頭
數據類型有d-整數,s-字符串,f-浮點數,b-二進制
.2是一個可選的寬度指標，小數點右邊輸出使用0填充
printf("%.2f",3.14159);
printf("%10.2f",3.14159);
printf("%.10f",3.14159);
printf("%.9s",abcdefghijklmn);
printf("%5.2f,%f,%7.3f\m",3.14159,3.14159,3.14159);
printf("%b %d %f %s \n",123,123,123,"test");
---------------------輸出結果----------------------------------------
3.14 3.143.1415900000abcdefghi 3.14,3.141590, 3.142\m1111011 123 123.000000 test
---------------------------------------------------------------------
2.字符串填充
string str_pad(string input原始字串, int length添加后的總長度[, string padding要填充的字符 [, int pad_type]填充類型])
填充類型有添加在左邊STR_PAD_LEFT，默認添在右邊，填充在兩端STR_PAD_BOTH
$index = array("one"=>1,"two"=>155,"three"=>1679);
echo "
";
echo str_pad("這是標題",50," ",STR_PAD_BOTH)."\n";
foreach($index as $inkey=>$inval)
echo str_pad($inkey,30,".").str_pad($inval,20,".",STR_PAD_LEFT)."\n";
echo "
";
---------------------輸出結果----------------------------------------
這是標題
one..............................................1
two............................................155
three.........................................1679
---------------------------------------------------------------------
string strtolower(string subject)/pic/p>
string strtoupper(string subject)/pic/p>
string ucfirst(string subject)/pic/p>
string ucwords(string subject)/pic/p>
string ltrim(string subject)/pic/p>
string rtrim(string subject)/pic/p>
string trim(string subject)去左右空白，空白包括null,制表符，換行符，回車符和空格
string n12br(string source)/pic/>標記
3.字符串比較
integer strcmp(sting str1,string str2) /pic/p>
integer strmcmp(sting str1,string str2,integer length) /pic/p>
print strcmp("aardvark","aardwolf");
print strncmp("aardvark","aardwolf",4);
---------------------輸出結果----------------------------------------
-10
---------------------------------------------------------------------
strcasecmp()和strncasecmp()是不區分大小寫的比較函數
4.查找和抽取子字符串
string substr(sting source,integer start[,integer length])/pic/p>
start和length可以使用負值
$var = "abcdefgh";
print substr($var,2);/pic/p>
print substr($var,2,3);
print substr($var,-1);/pic/p>
print substr($var,-5,2);
print substr($var,-5,-2);
---------------------輸出結果----------------------------------------
cdefgh
cde
h
de
def
---------------------------------------------------------------------
integer strpos(string haystack,string needle[,integer offset])/pic/p>
integer strrpos(string haystack,string needle)/pic/p>
還有常見的從 字符串中抽取找到的部分 的函數
string strstr(string haystack,string needle)/pic/p>
string stristr(string haystack,string needle)/pic/p>
string strrchr(string haystack,sting needle)
*********** array explode(string separator,string subject[,integer limit])/pic/p>
array implode(string glue,array pieces)/pic/p>
/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/代碼段/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/p>
$guest = "this is a string";
$guestArray = explode(" ",$guest);
var_dump($guestArray);
sort($guestArray);
echo implode(",",$guestArray);
/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/pic/p>
---------------------輸出結果----------------------------------------
array(4) { [0]=> string(4) "this" [1]=> string(2) "is" [2]=> string(1) "a" [3]=> string(6) "string" } a,is,string,this
---------------------------------------------------------------------
5.替換字符和子字符串
string substr_replace(string source,string replace,int start[,int length])
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