java 如何替换 LinkedHashMap 中特定键的值
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How to Replace the value in particular key in LinkedHashMap
提问by Abhinav singh
I want to replace the value in particular key in LinkedHashMap.
我想替换 LinkedHashMap 中特定键的值。
for example The initial Condition..
例如初始条件..
"key1" -> "value1"
"key2" -> "value2"
"key3" -> "value3"
"key4" -> "value4"
"key5" -> "value5"
I want to expected result...
我想要预期的结果...
"key1" -> "value1"
"key2" -> "value8"
"key3" -> "value3"
"key4" -> "value6"
"key5" -> "value5"
回答by Eran
You put a new value for that key :
您为该键设置了一个新值：
map.put("key2","value8");
map.put("key4","value6");
Note that for LinkedHashMap, changing the value for an existing key won't change the iteration order of the Map(which is the order in which the keys were first inserted to the Map).
请注意，对于LinkedHashMap，更改现有键的值不会更改 的迭代顺序Map（这是键首次插入到 Map 中的顺序）。
回答by Naman Gala
In Map(LinkedHashMap) key is the unique value. So whenever you try to put a value for a key, it will either add new entry in map or if key already exist then it will replace old value for that key with new value.
在 Map(LinkedHashMap) 中，键是唯一值。因此，无论何时您尝试为键输入值，它都会在映射中添加新条目，或者如果键已存在，则它将用新值替换该键的旧值。
map.put("existing key", "new value");
Above code will replace value of existing keyin map with new value.
上面的代码将existing key用new value.
回答by Rohith K
The proper way of checking if the key is present or not:
检查密钥是否存在的正确方法：
if (map.containsKey(key)) {
map.put("existing key", "newValue");
}
