Question

请解释为什么[s1]会从文档中返回此示例中的预期行为，但[s2]不会返回类似的结果？

#!/usr/bin/env ruby

s1 = [ "colors", "red", "blue", "green" ]
s2 = %w( letters, a, b, c )
s3 = "foo"

a = [ s1, s2, s3 ]

puts a.assoc "colors"
msg = a.assoc("colors").nil? ? "value is nil" : "value is true"
puts msg

puts a.assoc "letters"
msg = a.assoc("letters").nil? ? "value is nil" : "value is true"
puts msg

产地：

colors
red
blue
green
value is true

value is nil

Answer 1

%w notation期望项目由普通空格分隔：

# s2 = %w( letters, a, b, c ) # WRONG
  s2 = %w( letters a b c )    # CORRECT

Answer 2

您的s2数组变量

中有一些不必要的逗号

s2 = %w( letters, a, b, c )

所以你的a数组变量数组看起来像

[["colors", "red", "blue", "green"], ["letters,", "a,", "b,", "c"], "foo"]

因此，a.assoc "letters,"应该有效

puts a.assoc "letters,"
msg = a.assoc("letters,").nil? ? "value is nil" : "value is true"
puts msg

产地：

letters,
a,
b,
c
value is true

但是，mudasobwa's answer是正确的

%w notation期望项目由普通空格分隔：
# s2 = %w( letters, a, b, c ) # WRONG
  s2 = %w( letters a b c )    # CORRECT

#assoc对使用％w初始化的数组不起作用，为什么？

2 个答案: