声明list
list = [1,2,3]
list = (1..3).toList() //range转换为list
assert list == [1,3]
assert list[2] == 2
assert list instanceof java.util.List
list[2] = 12
assert list == [1,12,3]
longList = (0..100)
assert longList[22] == 22
list操作符
下标操作符
/** GDK使用range 和 collection作为参数重载了getAt()方法,这样就可以使用范围和索引的集合访问list */
list = [1,3,4]
assert list[0..2] == [1,3] //使用range访问list
assert list[0,2] ==[1,3] //使用集合访问list
list[0..2] = ['x','y','z']
assert list == ['x','z',4]
//当范围作为下标时,数量不一定要相等,当指定的列表值小于或者为空时,列表收缩
//当指定的列表值更大时,列表增长
list = [1,4]
list[1..2] = []
assert list == [3,4]
list = [1,4]
list[1..1] = [1,2]
assert list == [1,1,4]
//list可以通过负数进行索引
//-1表示最后一个。-2表示倒数第二个,以此类推
list = (0..3).toList()
assert list[-1] == 3
//当范围反向时,结果列表也是反向的
assert list[3..0] == [3,0]
//正负数可以一起使用 下式可以去掉开头和最后的元素
assert list[1..-2] == [1,2]
增删list中的元素
//+ plus方法
list = []
list += 1 //plus(Object)
list += [2,3] //plus(Collection)
assert list == [1,3]
list += (4..5)
assert list == [1,4,5]
//<< leftShift()方法
list << 6 <<7 //leftShift(Object)
assert list == [1,5,6,7]
list << [8,9]
assert list == [1,7,[8,9]]
list = [1,3]
list << (4..5) //4..5 字符串
assert list == [1,4..5]
//- minus()方法
list = [1,6]
assert list -= [5,6] == [1,4]
assert list -= (3..4) == [1,2]
assert list*2 == [1,2] //multiply(Object)
list方法
//add()类似于<<,但返回布尔值
list = [1,3]
list.add(4)
assert list == [1,4]
list = [1,3]
list.add(1,4)
assert list == [1,3] //在给定索引处插入新值
list = [1,3]
list.add([4,5])
assert list == [1,[4,5]]
list = [1,3]
list.add((1..2))
assert list == [1,1..2]
//addAll()类似于+,返回布尔值。
list = [1,3]
list.addAll([4,5]
list = [1,3]
list.addAll((4..5))
assert list == [1,5]
//get() getAt()
assert [1,3].get(1) == 2
assert [1,3].getAt([1,2]) == [2,3] //返回指定索引段的新列表
assert [1,3].getAt((0..1)) == [1,2]
assert [].isEmpty() //判断列表是否为空
assert [1,3].intersect([2,3]) == [2,3] //取交集,参数只能为列表
assert [1,4].disjoint([1]) //判断是否有交集 有则返回false;
assert [1,[3,4]].flatten() == [1,4] //打开嵌套的列表
assert [1,3].unique() == [1,3] //去重
assert new HashSet([1,1]).toList() == [1,3] //去重
assert [1,4].reverse() == [4,1] //反转
assert [1,7].sort() == [1,7] //升序
assert [1,7].sort{a,b -> b<=>a} == [7,1] //降序
assert [1,1].count(1) == 3 //计算包含元素的个数
assert list.join('-') == '1-2-3' //把所有的元素用给定字符串连接
assert list.join('') == '123'
[1,1].sum() //求和
[1,1].max() //求最大值
[1,1].min() //求最小值
//every() 所有的element都满足条件才返回true,否则返回false
assert list.every{it -> it<5}
//any() 只要存在一个满足条件的element就返回true,否则返回false
assert list.any{it -> it>2}
//像堆栈(stack)一样使用 push操作由<<代替 返回被删除的值
assert [1,3].pop()
assert [1,3].push(4) //返回布尔值
//通过下标删除元素 返回被删除的值
assert [1,4].remove(2) == [1,4]
//通过值删除符合条件的一个元素 返回布尔值
assert [1,'2',4].remove('2')
assert [1,1].removeAll(['2',3]) //删除所有符合条件的元素
//find() findAll() 返回符合条件的所有元素
def list = [1,4]
assert list.find{it -> it%2 ==0} ==2 //返回符合条件的一个元素
assert list.findAll{it -> it%2 ==0} == [2,4]
//grep() 符合条件的element会被提取出来,形成一个list
def list = ['a','ab','abc']
assert list.grep { elem -> elem.length()<3} == ['a','ab'] //条件以闭包形式传入
assert ["ab"] == list.grep(~/../) //条件以regex形式传入
assert ["a","ab"] == list.grep(['a','cde','ab']) //条件以列表形式传入
//each() 遍历list
store = ''
[1,3].each{it -> store += it}
assert store == '123'
//eachWithIndex() 带index的each
def list = []
['a','b','c'].eachWithIndex { elem,i ->list << "${elem}${i}"}
assert list == ["a0","b1","c2"]
//collect() 对集合每个元素进行运算后,得到一个新集合
def list = [1,4]
[2,8] == list.collect{it*2}
//groupBy() 对collection中的element按给定条件进行分组
def list = ['a','abc','c','bc']
assert [1:["a","b","c"],3:["abc"],2:["ab","bc"]] == list.groupBy { elem ->
elem.length()
}
//inject()方法遍历集合,第一次将传递的值和集合元素传给闭包,将处理结果作为传递的值,和下一个集合元素传给闭包,依此类推
result = list.inject(5){a,b -> a+=b}
assert result == 5 + 1+2+3
//transpose()方法实际上就是数学中矩阵的转置,简单的来说就是行和列的交换。如果List的长度不一,则取最短的长度
def list41 = [1,1]
def list51 = [2,2]
assert [[1,2],[1,2]] == [list41,list51].transpose()
tokenize() vs split()
//1.split()返回string[], tokenize()返回list
//2.tokenize()忽略空字符串
String testString = 'hello brother'
assert testString.split() instanceof String[]
assert ['hello','brother']==testString.split()
assert['he','','o brother']==testString.split('l')
assert testString.tokenize() instanceof List
assert ['hello','brother']==testString.tokenize()
assert ['he','o brother']==testString.tokenize('l')
//3.tokenize()使用字符串内的所有字符
String testString1='hello world'
assert ['hel',' world']==testString1.split('lo')
assert ['he',' w','r','d']==testString1.tokenize('lo')
//4.split()可以使用正则表达式
String testString2='hello world 123 herload'
assert['hello world ',' herload']==testString2.split(/\d{3}/)
集合应用
// 根据list内的map数组元素的元素有条件的去重,对name进行去重,age尽量不为空
def list = [['name':"zhangsan",'age':null],['name':"zhangsan",'age':23],['name':"lisi",'age':20],['name':"wangwu",'age':null]]
def ref = [];
list.each{
if(it.name in ref['name']){
name =it.name;
age = it.age;
ref.each{
if(it.name == name && it.age == null){
ref -= ["name":it.name,"age":it.age]
ref += ["name":name,"age":age]
}
}
}else{
ref += ["name":it.name,"age":it.age]
}
}
assert ref == [[name:zhangsan,age:23],[name:lisi,age:20],[name:wangwu,age:null]]
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