我有一个带有相同对象的列表。
我想通过两个属性对它们全部进行排序
名(从a到Z)
第二种类型(数字递增,例如1,2,3 ...)
void main() {
List<MyObject> list = List();
list.add(MyObject('Apple', 'definition of type #1'));
list.add(MyObject('Strawberry', 'definition of type #8'));
list.add(MyObject('Banana', 'definition of type #2'));
list.add(MyObject('Orange', 'definition of type #3'));
list.add(MyObject('Kiwi', 'definition of type #1'));
list.add(MyObject('Peach', 'definition of type #4'));
list.add(MyObject('Orange', 'definition of type #1'));
list.add(MyObject('Apple', 'definition of type #8'));
list.add(MyObject('Peach', 'definition of type #2'));
list.add(MyObject('Strawberry', 'definition of type #17'));
list.add(MyObject('Peach', 'definition of type #1'));
list.add(MyObject('Banana', 'definition of type #5'));
list.add(MyObject('Apple', 'definition of type #16'));
list.add(MyObject('Strawberry', 'definition of type #7'));
for (MyObject _object in list) {
print(_object.name + ' ' + _object.type);
}
RegExp regExp = new RegExp(
r"#'?.*",
);
list.sort((a, b) {
int _a = int.parse(regExp.stringMatch(a.type).replaceAll('#', ''));
int _b = int.parse(regExp.stringMatch(b.type).replaceAll('#', ''));
return _a
.compareTo(_b); //to get the order other way just switch `adate & bdate`
});
list.sort((a, b) => a.name.compareTo(b.name));
}
class MyObject {
String name;
String type;
MyObject(this.name, this.type);
}
我想要这样的输出,
Apple #1
Apple #8
Apple #16
Banana #2
Banana #5
...
我试图使用正则表达式方法解析数字(来自“类型为#(number)的定义”)
但是,如果我以此对列表进行排序,则无法将列表从a到Z(名称)进行排序
最佳答案
您只需要排序一次并定义排序方法,以便在名称相同的情况下比较类型:
void main() {
List<MyObject> list = List();
list.add(MyObject('Apple', 'definition of type #1'));
list.add(MyObject('Strawberry', 'definition of type #8'));
list.add(MyObject('Banana', 'definition of type #2'));
list.add(MyObject('Orange', 'definition of type #3'));
list.add(MyObject('Kiwi', 'definition of type #1'));
list.add(MyObject('Peach', 'definition of type #4'));
list.add(MyObject('Orange', 'definition of type #1'));
list.add(MyObject('Apple', 'definition of type #8'));
list.add(MyObject('Peach', 'definition of type #2'));
list.add(MyObject('Strawberry', 'definition of type #17'));
list.add(MyObject('Peach', 'definition of type #1'));
list.add(MyObject('Banana', 'definition of type #5'));
list.add(MyObject('Apple', 'definition of type #16'));
list.add(MyObject('Strawberry', 'definition of type #7'));
RegExp regExp = new RegExp(
r"#'?.*",
);
list.sort((a, b) {
int compare = a.name.compareTo(b.name);
if (compare == 0) {
int _a = int.parse(regExp.stringMatch(a.type).replaceAll('#', ''));
int _b = int.parse(regExp.stringMatch(b.type).replaceAll('#', ''));
return _a.compareTo(_b);
} else {
return compare;
}
});
for (MyObject _object in list) {
print(_object.name + ' ' + _object.type);
}
}
class MyObject {
String name;
String type;
MyObject(this.name, this.type);
}
输出:
Apple definition of type #1
Apple definition of type #8
Apple definition of type #16
Banana definition of type #2
Banana definition of type #5
Kiwi definition of type #1
Orange definition of type #1
Orange definition of type #3
Peach definition of type #1
Peach definition of type #2
Peach definition of type #4
Strawberry definition of type #7
Strawberry definition of type #8
Strawberry definition of type #17
关于dart - Dart按两个属性排序列表,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/61343000/