PHP test-specify a probability Random Number

A large company has the following PHP test questions:

 
Please write oneProgram, Randomly print "0", "1", "2", but ensure that "0", "1", "2" appear probability is configurable, such.
 

At first glance, the solution comes into being --

<? PHP  $ = $ B = $ C = 0 ;  $ Array = Array (0, 0, 1, 2, 2 );  For ( $ I = 1; $ I <1, 6001;$ I ++ ){  $ T = Array_rand ( $ Array  );  If ( $ T = 0 ){  $ ++ ;}  If ( $ T = 1 ){  $ B ++ ;}  If ( $ T = 2 ){  $ C ++ ;}}  Echo   $  ;  Echo "\ N" ;  Echo   $ B  ;  Echo "\ N";  Echo   $ C  ;  Echo "\ N" ; ?>

What is the result ~~~~

The probability is not controlled ~~~

Finally, I found a good method on the Internet. In fact, it's really easy to think about it. I just didn't turn it over. Hahaha ~~~

<? PHP  $ = $ B = $ C = 0 ;  For ( $ I = 1; $ I <1, 6001; $ I ++ ){  $ Temp = Rand (0, 60 );  If ( $ Temp <20 ){  $ ++ ;}  Elseif (20 <= $ Temp && $ Temp <30 ){  $ B ++ ;}  Else  {  $ C ++ ;}}  Echo   $  ;  Echo "\ N" ;  Echo   $ B  ;  Echo "\ N" ;  Echo   $ C  ;  Echo "\ N" ; ?>

Good results ~~

 

Rewrite to function:

<? PHP  Function Getrandom ( $ Array , $ Rate  ){  $ Rate = Explode (':',$ Rate  );  $ Sum = 0 ;  $ Left = 0 ;  $ Right = 0 ;  Foreach ( $ Rate   As   $ Value  ){  $ Sum + = $ Value * 10;}  $ Temp = Rand (0, $ Sum  );          Foreach ( $ Rate   As   $ Key => $ Value  ){  $ Right + = $ Value * 10 ;  If ($ Left <= $ Temp && $ Temp < $ Right  ){  Return   $ Array [ $ Key  ];}  $ Left + = $ Value * 10 ;}}  $ Array = Array (0, 1, 2, 3);  $ Rate = '2: 1: 3: 5' ;  $ = $ B = $ C = $ D = 0 ;  For ( $ I = 0; $ I <1, 1100; $ I ++ ){  If (Getrandom ($ Array , $ Rate ) = 0 ){  $ ++ ;}  If (Getrandom ( $ Array , $ Rate ) = 1 ){  $ B ++ ;}  If (Getrandom ( $ Array , $ Rate ) = 2 ){  $ C ++ ;}  If (Getrandom ( $ Array , $ Rate ) = 3 ){  $ D ++ ;}}  Echo   $  ;  Echo "\ N" ; Echo   $ B  ;  Echo "\ N" ;  Echo   $ C  ;  Echo "\ N" ;  Echo   $ D  ;  Echo "\ N" ; ?>