List类型

List - 集合类型,使用时用[]封装,中间数据用,分隔

定义List:List list = []

例:

List colors = ["red","blue","green","yellow"]

List类型的方法:

  • list.add(<Object any_type>):向列表添加元素

      返回值类型:Boolean

      例:

List colors = ["red", "blue", "green"]

colors.add("yellow") //返回:true

  • list.addAll(<List list1>):向列表添加多个元素

      返回值类型:Boolean

      例:

List colors = ["red", "blue"]

colors.addAll(["green", "yellow"]) //返回:true

  • list.clear():清空字符串

      返回值类型:无返回值

      例:

List colors = ["red", "blue"]

colors.clear()

  • list.contains(<Object any_type>):判断列表中是否存在指定元素。如果列表中存在元素, 则返回"true"

      返回值类型:Boolean

      例:

List colors = ["red", "blue", "green", "yellow"]

result = colors.contains("red") //返回:true

  • list.containsAll(<List list1>):判断列表中是否存在所有指定元素。如果列表中存在元素, 则返回"true"

      返回值类型:Boolean

      例:

List colors = ["red", "blue", "green"]

result = colors.containsAll(["red", "yellow"]) //返回:false

  • list.indexOf(<Object any_type>):返回给定元素在列表中的位置 (第一个元素的位置为 "0")

      返回值类型:BigDecimal

      例:

 List colors = ["red", "blue", "green", "yellow"]

 result = colors.indexOf("green") //返回:2

  • list.get(<BigDecimal indexNumber>):返回给定位置在列表中的元素 (第一个元素的位置为 "0")

      返回值类型:Object

      例:

 List colors = ["red", "blue", "green", "yellow"]

 result = colors.get(1) // 返回: "blue"

  • list.size():返回列表中元素的数目

      返回值类型:BigDecimal

      例:

List colors = ["red", "blue", "green", "yellow"]

result = colors.size() //返回:4

  • list.sort(<Boolean bool>)列表排序,可选布尔值指定升序 (true)/降序 (false),为空时默认为升序

      返回值类型:List

      例:

List colors = ["red", "blue", "green", "yellow"]

colors.sort() // 返回: ["blue","green","red","yellow"]

  • list.subList(<BigDecimal startIndex>,<BigDecimal endIndex>) 根据指定的开始和结束索引 (包含指定的索引) 从给定列表中返回一组元素

      返回值类型:List

      例:

List colors = ["red", "blue", "green", "yellow"]

result = colors.sublist(1, 3); // 返回: ["blue","green","yellow"]

  • list.remove(<BigDecimal index>)移除并返回指定索引处的元素 (第一个元素的索引为 "0")

      返回值类型:Object

      例:

 List colors = ["red", "blue", "green", "yellow"]

 colors.remove(2) // 返回: "green"

  • list.isEmpty()判断列表是否为空。返回一个布尔值-如果列表中不包含任何值, 则为true; 否则为-如果列表中包含值, 则为false

      返回值类型:Boolean

      例:

 List colors = ["red", "blue", "green", "yellow"]

 result = colors.isEmpty() // 返回: false

  • list.intersect(<List list>) 返回指定列表与当前列表的交集

      返回值类型:List

      例:

 colors = ["red", "blue", "green", "orange"]

 fruits = ["apple","orange","banana"]

 result = colors.intersect(fruits) // 返回:["orange"]

  • list.lastIndexOf(<Object any_type>) 返回指定元素在列表中的最后一个匹配项的位置

      返回值类型:BigDecimal

      例:

  colors = ["red", "blue", "green", "yellow", "green"]

  result = colors.lastIndexOf("green") //返回:4

  • list.eachWithIndex(<Closure closure>) 遍历列表中的数据,闭包中传入item和index

      返回值类型:List

      例:

  List list = ["a", "c"]

  list.eachWithIndex { item, int i ->

      log.info(item)

      log.info(i)

  } //运行日志:a  0  b  1

  • list.each(<Closure closure>) 遍历列表中的数据,闭包中传入item

      返回值类型:List

      例:

  List list = ["a", "c"]

  list.each { item -> 

      log.info(item)

  } //运行日志:a   b

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