Java 相关,用 list 去匹配 map 的 key,返回 map 的 value 的用法? - V2EX
V2EX = way to explore
V2EX 是一个关于分享和探索的地方
现在注册
已注册用户请  登录
KamL
V2EX    问与答

Java 相关,用 list 去匹配 map 的 key,返回 map 的 value 的用法?

  •  1
     
  •   KamL 2023-01-16 14:45:04 +08:00 1251 次点击
    这是一个创建于 1002 天前的主题,其中的信息可能已经有所发展或是发生改变。

    请问 java 中有没有 stream 的方法或者使用别的算法之类的去完成这个逻辑?

    我有: List<String> list; Map<String, Integer> keyMap;

    如果 list 的值命中 keyMap 里的 key 了,就返回一个 List<Integer> valueList 这样

    5 条回复    2023-01-17 09:24:39 +08:00
    Nooooobycat
        1
    Nooooobycat  
       2023-01-16 14:55:24 +08:00
    list.stream().map(keyMap::get).collect(Collectors.toList());

    这样可以吗
    superedlimited
        2
    superedlimited  
       2023-01-16 14:59:55 +08:00   1
    map.keyset().filter(el -> list.include(el)).map(el -> keyMap.get(el))
    Leviathann
        3
    Leviathann  
       2023-01-16 15:09:49 +08:00
    list
    filter get from map not null
    map
    issakchill
        4
    issakchill  
       2023-01-16 15:18:15 +08:00
    public <T> List<T> getByKeyList(Map<Integer, T> map, List<Integer> idList) {
    if (CollectionUtil.isEmpty(map) || CollectionUtil.isEmpty(idList)) {
    return new ArrayList<>();
    }

    return idList.stream()
    .map(map::get)
    .filter(Objects::nonNull)
    .collect(Collectors.toList());
    }
    KamL
        5
    KamL  
    OP
       2023-01-17 09:24:39 +08:00
    @Nooooobycat
    @superedlimited
    @Leviathann
    @issakchill
    感谢,昨天改 bug 改得头大,脑子转不过来了。谢谢大佬们!
    关于     帮助文档     自助推广系统     博客     API     FAQ     Solana     2971 人在线   最高记录 6679       Select Language
    创意工作者们的社区
    World is powered by solitude
    VERSION: 3.9.8.5 97ms UTC 13:43 PVG 21:43 LAX 06:43 JFK 09:43
    Do have faith in what you're doing.
    ubao snddm index pchome yahoo rakuten mypaper meadowduck bidyahoo youbao zxmzxm asda bnvcg cvbfg dfscv mmhjk xxddc yybgb zznbn ccubao uaitu acv GXCV ET GDG YH FG BCVB FJFH CBRE CBC GDG ET54 WRWR RWER WREW WRWER RWER SDG EW SF DSFSF fbbs ubao fhd dfg ewr dg df ewwr ewwr et ruyut utut dfg fgd gdfgt etg dfgt dfgd ert4 gd fgg wr 235 wer3 we vsdf sdf gdf ert xcv sdf rwer hfd dfg cvb rwf afb dfh jgh bmn lgh rty gfds cxv xcv xcs vdas fdf fgd cv sdf tert sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf shasha9178 shasha9178 shasha9178 shasha9178 shasha9178 liflif2 liflif2 liflif2 liflif2 liflif2 liblib3 liblib3 liblib3 liblib3 liblib3 zhazha444 zhazha444 zhazha444 zhazha444 zhazha444 dende5 dende denden denden2 denden21 fenfen9 fenf619 fen619 fenfe9 fe619 sdf sdf sdf sdf sdf zhazh90 zhazh0 zhaa50 zha90 zh590 zho zhoz zhozh zhozho zhozho2 lislis lls95 lili95 lils5 liss9 sdf0ty987 sdft876 sdft9876 sdf09876 sd0t9876 sdf0ty98 sdf0976 sdf0ty986 sdf0ty96 sdf0t76 sdf0876 df0ty98 sf0t876 sd0ty76 sdy76 sdf76 sdf0t76 sdf0ty9 sdf0ty98 sdf0ty987 sdf0ty98 sdf6676 sdf876 sd876 sd876 sdf6 sdf6 sdf9876 sdf0t sdf06 sdf0ty9776 sdf0ty9776 sdf0ty76 sdf8876 sdf0t sd6 sdf06 s688876 sd688 sdf86