How to generate a random string in php

* $ Validcharacters & quot; abcdefghijklmnopqrstuxyvwzabcdefghijklmnopqrstuxyvwz +-* & amp ;@!? & Quot; $ indexmt_rand (); echo $ index; look at a complicated one

1. */
2. $ Validcharacters = "abcdefghijklmnopqrstuxyvwzabcdefghijklmnopqrstuxyvwz + -*#&@!? ";
3. $ Index = mt_rand (0, 10 );
4. Echo $ index;
5. // Look at a complicated one
6. $ Validcharacters = "abcdefghijklmnopqrstuxyvwzabcdefghijklmnopqrstuxyvwz + -*#&@!? ";
7. $ Validcharnumber = strlen ($ validcharacters );
8. $ Index = mt_rand (0, $ validcharnumber-1 );
9. $ Randomcharacter = $ validcharacters [$ index];
10. Echo $ randomcharacter;
11. // Instance 2
12. $ Length = 5;
13. $ Result = "";
14. For ($ I = 0; $ I <$ length; $ I ++ ){
15. $ Index = mt_rand (0, $ validcharnumber-1 );
16. $ Result. = $ validcharacters [$ index];
17. }
18. //
19. Function getrandomstring ($ length = 6 ){
20. $ Validcharacters = "abcdefghijklmnopqrstuxyvwzabcdefghijklmnopqrstuxyvwz + -*#&@!? ";
21. $ Validcharnumber = strlen ($ validcharacters );
22. $ Result = "";
23. For ($ I = 0; $ I <$ length; $ I ++ ){
24. $ Index = mt_rand (0, $ validcharnumber-1 );
25. $ Result. = $ validcharacters [$ index];
26. }
27. Return $ result;
28. }
29. Echo getrandomstring ();