11 2016 档案
摘要:1. 基本原理: 通过hadoop fs -ls *命令获取相关文件或目录的修改时间,然后与设定的过期时间进行比较,之后执行删除操作即可 2. 相关代码: 参考:Hadoop运维-删除目录下过期的数据
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摘要:Scala's object-oriented collections support mutable and immutable type hierarchies. Also support functional higher-order operations such as map, filte
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摘要:The basic functional cornerstones of Scala: immutable data types, passing of functions as parameters and pattern matching. 1. Basic Pattern Matching I
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摘要:1. Functional programming treats computation as the evaluation of mathematical and avoids state and mutable data. Scala encourages an expression-orien
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摘要:1. The three principles of OOP are encapsulation(封装性), inheritance(继承性) and polymorphism(多态性). example: A subtype is guaranteed to have all the member
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摘要:1. Variables (1) Three ways to define variables: 1) val refers to define an immutable variable; 2) var refers to define a mutable variable. 3) lazy va
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摘要:1. Scala is a contraction of "scalable" and "language". It's a fusion of objected-oritended and functional programming. 2. Compare Book class between
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