Question

我需要从如下所示的.txt文件中找到唯一的姓氏：

Kent, Mackenna -- ut
    Voluptatem ipsam et at.
Marven, Gardens -- non
    Facere et necessitatibus animi.
McLaughlinn, Matt -- consequatur
    Eveniet temporibus ducimus amet eaque.
Lang, August -- pariatur
    Unde voluptas sit fugit.
Brad, Nick -- et
    Maiores ab officia sed.
Adam, Levine -- error
    Repellendus alias officia amet et perspiciatis.
Learner, York -- nesciunt
    Incidunt et ut necessitatibus porro.
Ortiz, Andrew -- fuga
    Tempore eos et hic.
Lang, Bryant -- et
Laborum perferendis inventore eveniet.

到目前为止，我有：

FNAME = 'example.txt'

# maps for last name in file
def last_name_from_file(file_name)
  last_name = File.readlines(file_name).reject(&:empty?)
  last_name.map do |line|
    line.split.first
  end
end
puts last_name_from_file('example.txt')

但是这给了我输出，其中包括Lorem文本和姓氏。

#Kent
#Voluptatem
#Marven
#Facere
#McLaughlinn
#Eveniet
#Lang
#Unde
#Brad
...

Answer 1

我看到lorem行是偶数，所以您可以拒绝它们。

def last_name_from_file(file_name)
  File.
    readlines(file_name).
    reject.
    with_index(1) { |_, id| id.even? }.
    map { |line| line.split(',').first }.
    uniq
end

好吧，我该如何获得名字？

您可以执行以下方法：

def names(file_name)
  File.
    readlines(file_name).
    reject.
    with_index(1) { |_, id| id.even? }.
    map { |line| line.split(' --').first.split(', ') }.
    map { |ln, fn| { lastname: ln, firstname: fn } }
end

现在您可以调用它：

names = names('example.txt')

names
# => [{:lastname=>"Kent", :firstname=>"Mackenna"}, {:lastname=>"Marven", :firstname=>"Gardens"}, {:lastname=>"McLaughlinn", :firstname=>"Matt"}, {:lastname=>"Lang", :firstname=>"August"}, {:lastname=>"Brad", :firstname=>"Nick"}, {:lastname=>"Adam", :firstname=>"Levine"}, {:lastname=>"Learner", :firstname=>"York"}, {:lastname=>"Ortiz", :firstname=>"Andrew"}, {:lastname=>"Lang", :firstname=>"Bryant"}]

names.map { |name| name[:lastname] }
# => ["Kent", "Marven", "McLaughlinn", "Lang", "Brad", "Adam", "Learner", "Ortiz", "Lang"]

names.map { |name| name[:firstname] }
# => ["Mackenna", "Gardens", "Matt", "August", "Nick", "Levine", "York", "Andrew", "Bryant"]

Answer 2

类似于昨天的my answer：

def last_name_from_file(fname)
  File.open(fname, "r").each_with_object([]).with_index do |(line, o), i|
    o << line.split(',').first if i.even?
  end.uniq
end

puts last_name_from_file('example.txt')

#Kent
#Marven
#McLaughlinn
#...

Answer 3

让我们创建文件。

FName = 'temp.txt'

IO.write(FName,
<<~END
Kent, Mackenna -- ut
    Voluptatem ipsam et at.
Marven, Gardens -- non
    Facere et necessitatibus animi.
McLaughlinn, Matt -- consequatur
    Eveniet temporibus ducimus amet eaque.
Lang, August -- pariatur
    Unde voluptas sit fugit.
Brad, Nick -- et
    Maiores ab officia sed.
Adam, Levine -- error
    Repellendus alias officia amet et perspiciatis.
Learner, York -- nesciunt
    Incidunt et ut necessitatibus porro.
O'Conner-Bolonzo, Andrew -- fuga
    Tempore eos et hic.
Lang, Bryant -- et
Laborum perferendis inventore eveniet.
END
)
  #=> 539

我们可以通过逐行读取文件，逐行读取来提取唯一的姓氏；无需将文件插入数组。

require 'set'

IO.foreach(FName).each_with_object(Set.new) do |line,set|
   last_name = line[/\A[\p{Alpha}'-]+(?=,)/]
   set << last_name unless last_name.nil?
end.to_a
  #=> ["Kent", "Marven", "McLaughlinn", "Lang", "Brad", "Adam", "Learner",
  #    "O'Conner-Bolonzo"]

请参见IO::foreach，Enumerable#each_with_object，Set::new，Set#to_a和String#[]。

请注意，IO::foreach在未分配块时会返回一个枚举数，因此可以在此处链接到Enumerable#each_with_object。

String#[]使用的正则表达式读取“立即匹配字符串（+）开头的一个或多个（\A）字符，即字母，撇号或连字符然后是逗号。”

从Ruby中的.txt文件中查找唯一的姓氏

3 个答案: