erlang中修改list裡面tuple—list的值的類型

2020-11-12 12:49:00

有個這樣的例子：list裡面是多個個tuple—list 或者maps，

ListA = [[{},{}}],[{},{}]], 舉例：

A = [[{<<"CARDISSUERID">>,<<"2">>},
{<<"CARDSTOCKTYPE">>,1},
{<<"CARDTYPE">>,0},
{<<"DERIVATIVESPRODUCTTYPE">>,1},
{<<"PARAM_VER">>,<<"195">>},
{<<"PREASSIGNMENTATTRIBUTE">>,1},
{<<"PRODUCTTYPE">>,9800},
{<<"SALEVALUE">>,<<"0">>}],
[{<<"CARDISSUERID">>,<<"2">>},
{<<"CARDSTOCKTYPE">>,1},
{<<"CARDTYPE">>,0},
{<<"DERIVATIVESPRODUCTTYPE">>,1},
{<<"PARAM_VER">>,<<"195">>},
{<<"PREASSIGNMENTATTRIBUTE">>,1},
{<<"PRODUCTTYPE">>,9800},
{<<"SALEVALUE">>,<<"0">>}]].

　　想把 key是 <<"CARDISSUERID">> 的值的類型，改成integer ，目前是 binary ，{<<"CARDISSUERID">>,<<"2">>}

直接上代碼，修改對應key的值，直接幹：

[lists:map(fun(X) -> if element(1,X) == <<"CARDISSUERID">> -> 
                                     {element(1,X), binary_to_integer(element(2,X))};
                            true -> X
                     end 
                end,Z)|| Z<-A].

　執行結果如下：