Substr functions of PHP

Substr (); substr (str, start, length); example: substr (phpisverygoodlanguage,); output as isve; when start & gt; str length, returns (); substr (phpisverygoodlanguage,); substr (phpisverygoodlan substr ();
Substr (str, start, length );
Example: substr (php is very good language, 4, 5 );
Output is ve;

If the length of start> str is returned ();
Substr (php is very good language, 26, 5 );
Substr (php is very good language, 4 );
Output as (blank)
Output is v (both start and langth are 4)

When start is a negative value, it starts to read from the end of str (* at this time, it starts to read from-1 rather than from 0 ),
Substr (php is very good language,-4, 5 );
Output as uage

When the value of length is negative, length indicates reading from the end and intercepting the end position of str.
Substr (php is very good language, 4,-5 );
Output is very good lan
Explode () splits function strings into arrays;
Strrev () returns the function string
Setlocalhost (content location) sets the local environment. content, and specifies the scenario information constants to be set include (
LC_ALL? Constants of all subordinates
LC_COLLATE? Sort order
LC_CTYPE? Character classification and conversion (for example, converting all characters into lowercase or upper case)
LC_MESSAGES? System Information format
LC_MONETARY? Currency/currency format
LC_NUMERIC? Value Format
LC_TIME? Date and time format
); Location, set the country region, for example, chs.
Strftime () format the local time/date according to the region.