Ruby 中 each.with_index 和 each_with_index 之间的区别? [英] difference between each.with_index and each_with_index in Ruby?

问题描述

我真的很困惑each.with_index 和each_with_index 之间的区别.它们有不同的类型，但在实践中似乎是相同的.

I'm really confused about the difference between each.with_index and each_with_index. They have different types but seem to be identical in practice.

推荐答案

with_index 方法采用一个可选参数来偏移起始索引.each_with_index 做同样的事情，但没有可选的起始索引.

The with_index method takes an optional parameter to offset the starting index. each_with_index does the same thing, but has no optional starting index.

例如:

[:foo, :bar, :baz].each.with_index(2) do |value, index|
    puts "#{index}: #{value}"
end

[:foo, :bar, :baz].each_with_index do |value, index|
    puts "#{index}: #{value}"
end

输出:

2: foo
3: bar
4: baz

0: foo
1: bar
2: baz

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