Ruby Enumerator::lazy

< Span class= "S1" > < span class= "n" > < Span class= "o" >  
 
 when a large array or collection needs to be looped, it can be a big disadvantage to put the data into memory at once. This is where lazy comes in handy. 
                 /span>                Float::INFINITY 是无穷大意思

举个例子 取出1到无穷大对7整除余数为0的前10个数值。

(1..float::infinity). Select {|x| x% 7 = = 0}.take (ten). to_a

This writing will directly die, this time with lazy

(1..float::infinity). lazy.select {|x| x% 7 = = 0}.take (ten). to_a

Similarly, when we operate a very large file, the direct each_line operation will put the entire file into memory.

File = File.Open ('xxxx'r' |row| row.xxx}

The lazy method will load the file incrementally.

File = File.Open ('xxxx'r' |row| row}

　　

Detailed usage of Enumerator::lazy:

https://railsware.com/blog/2012/03/13/ruby-2-0-enumerablelazy/

< Span class= "NF" > < span class= "n" > < Span class= "NF" >  
 
 
         /span>                 

Ruby Enumerator::lazy