Dataweave 2.2 takeWhile 和 filter 有什么区别？

Question

%dw 2.0
import * from dw::core::Arrays
output application/json
var arr = [0,1,2,4,3]
---
arr filter $ <= 2

和

%dw 2.0
import * from dw::core::Arrays
output application/json
var arr = [0,1,2,4,3]
---
arr takeWhile $ <= 2

它们都给出了相同的结果。有区别吗？

Answer 1

嗨，戴尔，有一个区别 takeWhile 将停止获取第一个不满足条件的元素，这不是过滤器的情况，所以对于这个例子 [0,2,4,3 ,1]

使用 TakeWhile

%dw 2.0
import * from dw::core::Arrays
output application/json
var arr = [0,2,4,3,1]
---
arr takeWhile $ <= 2

Returns:

[
  0,
  2
]

有过滤器

%dw 2.0
import * from dw::core::Arrays
output application/json
var arr = [0,2,4,3,1]
---
arr filter $ <= 2

Returns:

[
  0,
  2,
  1
]

Answer 2

takeWhile ：在满足条件时从数组中选择元素，但在到达不满足条件的元素时停止 selection 过程。

脚本

%dw 2.0
import * from dw::core::Arrays
output application/json
var arr = [0,2,4,3,1]
---
arr takeWhile $ <= 2

输出

[
  0,
  2
]

filter ：对select所有满足条件的元素，使用函数。脚本

%dw 2.0
import * from dw::core::Arrays
output application/json
var arr = [0,2,4,3,1]
---
arr filter $ <= 2

输出

[
  0,
  2,
  1
]

Dataweave 2.2 What's the difference between takeWhile and filter?