过滤咖啡脚本中的记录数组以返回年龄> 50的所有记录

Posted 2023-03-03

【中文标题】过滤咖啡脚本中的记录数组以返回年龄> 50的所有记录

【英文标题】：Filtering an array of records in coffeescript to return all records with age > 50

【发布时间】：2018-07-10 05:27:05

【问题描述】：

鉴于这种数据集

records = [
  id: 1, name: "John Smith", age: 49,
  id: 2, name: "Jane Brown", age: 45,
  id: 3, name: "Tim Jones",  age: 60,
  id: 4, name: "Blake Owen", age: 78    
]

如何过滤记录以返回刚刚超过 50 岁的缩减数组。

说返回数组是

over50s = // something

我查看了很多类似的代码，但它们对我来说非常融合。

感谢您的帮助！

【参考方案1】：

这个示例脚本怎么样？使用filter() 检索结果over50s。

示例脚本：

records = [
  id: 1, name: "John Smith", age: 49,
  id: 2, name: "Jane Brown", age: 45,
  id: 3, name: "Tim Jones",  age: 60,
  id: 4, name: "Blake Owen", age: 78
]
over50s = records.filter (e) -> e.age >= 50

结果：

[
     id: 3, name: 'Tim Jones',  age: 60 ,
     id: 4, name: 'Blake Owen', age: 78 
]

如果我误解了你的问题，请告诉我。我要修改。

【参考方案2】：

答案很完美，但我想使用comprehensions添加“Coffeescript方式”：

 over50s = (record for record in records when record.age > 50)

解释：

for record in records
  console.log(record)
# This would loop over the records array, 
#   and each item in the array will be accessible 
#   inside the loop as `record`

console.log(record) for record in records
# This is the single line version of the above

console.log(record) for record in records when record.age > 50
# now we would only log those records which are over 50

over50s = (record for record in records when record.age > 50)
# Instead of logging the item, we can return it, and as coffeescript
#   implicitly returns from all blocks, including comprehensions, the 
#   output would be the filtered array
# It's shorthand for:
    
over50s = for record in records
  continue unless record.age > 50
  record

# This long hand is better for complex filtering conditions. You can
#   just keep on adding `continue if ...` lines for every condition
# Impressively, instead of ending up with `null` or `undefined` values
#   in the filtered array, those values which are skipped by `continue`
#   are completely removed from the filtered array, so it will be shorter.

【讨论】：

谢谢。我最初搜索时看到了这种风格..我如何阅读“记录记录”部分？例如，你碰巧知道第一个“记录”取得了什么成就吗？谢谢

如果你要使用单行，你必须小心你的括号：over50s = (record for record in records when record.age > 50)。否则，您只是为每个 record 说 over50s = record。

@muistooshort 很好，我在咖啡壳中测试过，但我只看到了理解的输出，over50s var 从未设置