Some common string functions in PHP

//examgle
$title = "  Programming PHP  \n";
$str1 = ltrim($title);//Promgromming PHP \n
$str2 = rtrim($title);//  Programming PHP
$str3 = trim($title);//Programming PHP

//可以使用带参数的trim()函数来删除开头或结尾的空白而不删除制表符
$record = " Fred\tFlintstone\t35\tWilma\t  \n";
$record = trim($record, " \r\n\0\x0B");
//此时record 值为："Fred\tFlintstone\t35\tWilma\t"

//example
$str1 = "FRED fintstone";
$str2 = "barney rubble" ;
print(strtolower($str1));
print(strtoupper($str1));
print(ucfirst($str2));
print(ucwords($str2));

//输出
fred fintstone
FRED FINTSTONE
Barney rubble
Barney Rubble