Learning PHP notes-substr (), explode (), strrev ()

Substr (STR, start, length );

Example: substr ('php is very good language );

Output is ve;

If the length of Start> STR is returned ();

Substr ('php is very good language );

Substr ('php is very good language ',4);

Output as (blank)

Output is V (It indicates that 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 );

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;

// Example 1
$ Pizza = "piece1 piece2 piece3 piece4 piece5 piece6 ";
$ Pieces = explode ("", $ pizza );
Echo $ pieces [0]; // piece1
Echo $ pieces [1]; // piece2

// Example 2
$ DATA = "foo: *: 1023: 1000:/home/FOO:/bin/sh ";
List ($ user, $ pass, $ uid, $ GID, $ GECOS, $ home, $ shell) = explode (":", $ data );
Echo $ GECOS. "<br>"; // foo
Echo $ shell ;//*

Strrev () outputs the string from the back to the front

Echo strrev ("June"); // outputs "enuj"

Setlocalhost(Content location) to set the local environment. Content, specify the scenario information constants to be set (

• 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-numeric format
• Lc_time-Date and Time Format

); Location, set the country region, for example, chs.