匹配/替换函数

shijiang1130

1. Erlang/OTP 17 [erts-6.0] [64-bit] [smp:4:4] [async-threads:10]
   
2. 
   
3. Eshell V6.0  (abort with ^G)
   
4. 1> A = <<"Chinaunix is here">>.  
   
5. <<"Chinaunix is here">>
   
6. 2> l(re).   
   
7. {module,re}
   
8. 3> re:
   
9. compile/1      compile/2      grun/3         inspect/2      module_info/0  
   
10. module_info/1  replace/3      replace/4      run/2          run/3         
    
11. split/2        split/3        ucompile/2     urun/3         
    
12. 3> re:replace(A,<<here>>,<<there>>).
    
13. ** exception error: bad argument
    
14. 4> re:replace(A,<<"here">>,<<"there">>).
    
15. [<<"Chinaunix is ">>,<<"there">>]
    
16. 5> re:replace(A,<<"here">>,<<"there">>,[{return,binary}]).
    
17. <<"Chinaunix is there">>
    
18. 6>

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1. 6> f().
   
2. ok
   
3. 7> A = ["aaa","bbb","ccc"].
   
4. ["aaa","bbb","ccc"]
   
5. 8> [X,Y|_] = A.
   
6. ["aaa","bbb","ccc"]
   
7. 9> X.
   
8. "aaa"
   
9. 10> Y.
   
10. "bbb"

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1. 11> f().
   
2. ok
   
3. 12> B={o,p,q,r,s,t}.
   
4. {o,p,q,r,s,t}
   
5. 13> {_,_,X,_} = B.
   
6. ** exception error: no match of right hand side value {o,p,q,r,s,t}
   
7. 14> {_,_,X,_,_,_} = B.
   
8. {o,p,q,r,s,t}
   
9. 15> X.
   
10. q
    
11. 16>

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1. 16> f().
   
2. ok
   
3. 17>
   
4. 17> A = <<"Chinaunix is here">>.                           
   
5. <<"Chinaunix is here">>
   
6. 18> binary:re
   
7. referenced_byte_size/1  replace/3               replace/4               
   
8. 
   
9. 18> binary:replace(A,<<"Chinaunix">>,<<"CU">>).
   
10. <<"CU is here">>
    
11. 19>

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crazyhadoop

准确说是匹配/替换模式，  “=” 是非常重要的模式匹配符。