1 % ******************************************************************************
2 % ------------------------------------------------------------------------------
3 % 习题 5
4 % 合并列表，A=[{a,1},{b,2},{c,3},{b,1}],B=[{b,4},{c,5},{d,6},{d,2}].
5 % 结果：[{a,1},{b,7},{c,8},{d,8}]
6 % D=[{a,3},{f,14},{k,39},{f,22},{g,88},{d,23}].
7 % 把B列表合并到A列表，新增的放后面，不能用++
8 % ------------------------------------------------------------------------------
9
10
11 test5( A, B ) ->
12 M = test5a_2( A,[] ),
13 test5a_2( B, M ).
14
15 test5a_1( E, [Th|T], F, R ) ->
16 {Flag,V} = match(E ,Th),
17 test5a_1( E, T, Flag or F, [V|R] );
18 test5a_1( E, [], F, R ) ->
19 case F of
20 true ->
21 R;
22 false ->
23 [E|R]
24 end.
25
26 test5a_2( [Th|T], R ) ->
27 M = test5a_1( Th, R, false, [] ),
28 Mr= lists:reverse(M),
29 test5a_2( T, Mr ) ;
30 test5a_2( [], R ) ->
31 R.
32
33
34 % 匹配成功，返回处理后的值，失败返回匹配B值
35 match( {Nam,ValA}, {Nam,ValB} ) ->
36 { true, {Nam,ValA+ValB} } ;
37 match( _, Th ) ->
38 { false, Th }.
