英文:
How remove the specific value from map in dart?
问题
我是Flutter的初学者，正在学习地图概念。我对地图的方法感到困惑。如何从地图中删除特定的值？
例如：
Map data = {
"studet1": {"name": "ajk", "age": "22", "place": "delhi"},
"studet2": {"name": "akmal", "age": "25", "place": "up"}
};
我想从"student1"中删除"name"。
英文:
I am Beginner in flutter, learning map concept. I am confusing map methods. How to delete a specific value from a map?
for example:
Map data = {
"studet1": {"name": "ajk", "age": "22", "place": "delhi"},
"studet2": {"name": "akmal", "age": "25", "place": "up"}
};
I want to delete the "name" from "student1".
答案1
得分: 5
data 是一个嵌套的 map，意味着它在 student1 这个键内包含另一个 map。
你可以使用 .remove 方法来从 map 中删除一个键：
> 如果存在，从 map 中删除 key 及其关联的值。
void main() {
Map data ={
"student1":{
"name" : "ajk",
"age":"22",
"place":"delhi"
},
"student2":{
"name" : "akmal",
"age":"25",
"place":"up"
}
};
data['student1'].remove('name');
print(data);
}
打印结果:
{student1: {age: 22, place: delhi}, student2: {name: akmal, age: 25, place: up}}
英文:
data is a nested map, which means that it has another map within the key of student1.
You can use the .remove method to remove a key within a map:
> Removes key and its associated value, if present, from the map.
void main() {
Map data ={
"student1":{
"name" : "ajk",
"age":"22",
"place":"delhi"
},
"student2":{
"name" : "akmal",
"age":"25",
"place":"up"
}
};
data['student1'].remove('name');
print(data);
}
Prints:
{student1: {age: 22, place: delhi}, student2: {name: akmal, age: 25, place: up}}
答案2
得分: 2
如果您只想删除student1的名字，请使用以下代码：
data['student1'].remove('name');
或者，如果您想删除所有学生的名字，请使用以下方法：
Map data = {
"student1": {"name": "ajk", "age": "22", "place": "delhi"},
"student2": {"name": "akmal", "age": "25", "place": "up"}
};
for (int i = 0; i <= data.length - 1; i++) {
data[data.keys.elementAt(i)].remove('name');
}
输出将是：
{student1: {age: 22, place: delhi}, student2: {age: 25, place: up}}
英文:
If you want to remove only student1 name
Just use data['student1'].remove('name');
Or if you want to remove all students name use the bleow method
Map data = {
"studet1": {"name": "ajk", "age": "22", "place": "delhi"},
"studet2": {"name": "akmal", "age": "25", "place": "up"}
};
for (int i = 0; i <= data.length - 1; i++) {
data[data.keys.elementAt(i)].remove('name');
}
The output will be
{student1: {age: 22, place: delhi}, student2: {age: 25, place: up}}
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