list common properties and methods
common property
1,length gets the length of list
main() { var list = ['red','yellow','pink']; print(list.length); }
2, judge whether it is empty
main() { var list = ['red','yellow','pink']; print(list.isEmpty); }
3, not null
main() { var list = ['red','yellow','pink']; print(list.isNotEmpty); }
4, the array flips
main() { var list = ['red','yellow','pink']; print(list.reversed.toList()); } (pink, yellow, red)
common method
1, add data
main() { var list = ['red','yellow','pink']; list.add("green"); print(list); } [red, yellow, pink, green]
2, find data indexOf, find return index, can’t find return -1
main() { var list = ['red','yellow','pink']; var res = list.indexOf('yellow'); print(res); } 1
3, removed data (‘ value ‘),removeAt(index)
main() { var list = ['red','yellow','pink']; list.remove('yellow'); list.removeAt(1); print(list); } [red]
4, modify data fillRange(start,end,value) without end
main() { var list = ['red','yellow','pink']; list.fillRange(1, 2,'green'); print(list); } [red, green, pink]
5, insert data insert(index,value) to the specified position. Insert
from index
main() { var list = ['red','yellow','pink']; list.insert(1, 'green'); print(list); } [red, green, yellow, pink] main() { var list = ['red','yellow','pink']; list.insertAll(1, ['green','white']); print(list); } [red, green, white, yellow, pink]
6, convert to string join(‘, ‘), instead of the original list
main() { var list = ['red','yellow','pink']; var str = list.join(','); print(str); } red,yellow,pink
7, convert string to array split(‘ – ‘), do not change the original string
main() { var str = 'red-yellow-pink'; var list = str.split('-'); print(list); print(str); } [red, yellow, pink] red-yellow-pink
8, for(var item in list) loop list
main() { var list = ['red','yellow','pink']; for(var item in list) { print(item); } } red yellow pink
9,map loop list
main() { var list = [1,2,3,4]; var newList = list.map((value) => value * 2); print(newList.toList()); }
10, see if the set satisfies some condition any
main() { var list = ['red','yellow','pink']; var f = list.any((value) => value == 'red'); print(f); print(list); }
11, through the set can not add repeated collection, so can not get
through the index
main() { var set = new Set(); set.add('red'); set.add('yellow'); set.add('pink'); set.add('red'); print(set.toList()); } [red, yellow, pink]
maps type common properties and methods
1, get all keys
main() { var person = { 'name':'张三', 'age':20, }; print(person.keys.toList()); } [name, age]
2, get all values
main() { var person = { 'name':'张三', 'age':20, }; print(person.values.toList()); }
3, determine whether the attribute isEmpty isEmpty
main() { var person = { 'name':'张三', 'age':20, }; print(person.isEmpty); } false
common method
1, remove the specified key data (key)
main() { var person = { 'name':'张三', 'age':20, }; person.remove('name'); print(person); } {age: 20}
2, addAll({‘ key ‘:’ value ‘})
main() { var person = { 'name':'张三', 'age':20, }; person.addAll({ 'sex':'男', }); print(person); } {name: 张三, age: 20, sex: 男}
3, check to see if the fields are in the map containsKey(key), return true/false does not change the original pair like
main() { var person = { 'name':'张三', 'age':20, }; var boo = person.containsKey('name'); print(boo); } true
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