Question

我正在研究Chris Pine的Learn to Program一书中的一个示例问题，我在删除哈希值中的空格时遇到了问题。

我从一个包含姓名和生日信息的txt文件开始，如下所示：

Christopher Alexander,  Oct  4, 1936
Christopher Lambert,    Mar 29, 1957
Christopher Lee,        May 27, 1922
Christopher Lloyd,      Oct 22, 1938
Christopher Pine,       Aug  3, 1976

然后我遍历每一行，在第一个逗号分割，然后尝试遍历每个键，值以去除空白区域。

birth_dates = Hash.new {}

File.open 'birthdays.txt', 'r' do |f|
  f.read.each_line do |line|
  name, date = line.split(/,/, 2)
  birth_dates[name] = date
  birth_dates.each_key { |a| birth_dates[a].strip! }
end

但没有任何事情被剥夺。

{"Christopher Alexander"=>"  Oct  4, 1936", "Christopher Lambert"=>"    Mar 29, 1957", "Christopher Lee"=>"        May 27, 1922", "Christopher Lloyd"=>"      Oct 22, 1938", "Christopher Pine"=>"       Aug  3, 1976", "Christopher Plummer"=>"    Dec 13, 1927", "Christopher Walken"=>"     Mar 31, 1943", "The King of Spain"=>"      Jan  5, 1938"}

我已经看到了一些使用.map的数组解决方案 - 但这是我遇到的唯一哈希示例。知道为什么它可能不适合我吗？

更新：根据sawa的评论删除多余的chomp。

Answer 1

对于解析逗号分隔文件，我使用像这样的

def parse_birthdays(file='birthdays.txt', hash={})
  CSV.foreach(file, :converters=> lambda {|f| f ? f.strip : nil}){|name, date, year|hash[name] = "#{year}-#{date.gsub(/ +/,'-')}" }
  hash
end
parse_birthdays
# {"Christopher Alexander"=>"1936-Oct-4", "Christopher Lambert"=>"1957-Mar-29", "Christopher Lee"=>"1922-May-27", "Christopher Lloyd"=>"1938-Oct-22", "Christopher Pine"=>"1976-Aug-3"}

如果您需要真实日期，可以放弃lambda

def parse_birthdays(file='birthdays.txt', hash={})
  CSV.foreach(file){|name, date, year|hash[name] = Date.parse("#{year}-#{date}")}
  hash
end
parse_birthdays
# {"Christopher Alexander"=>#<Date: 2014-10-04 ((2456935j,0s,0n),+0s,2299161j)>, "Christopher Lambert"=>#<Date: 2014-03-29 ((2456746j,0s,0n),+0s,2299161j)>, "Christopher Lee"=>#<Date: 2014-05-27 ((2456805j,0s,0n),+0s,2299161j)>, "Christopher Lloyd"=>#<Date: 2014-10-22 ((2456953j,0s,0n),+0s,2299161j)>, "Christopher Pine"=>#<Date: 2014-08-03 ((2456873j,0s,0n),+0s,2299161j)>}

Answer 2

我会写这个

File.open 'birthdays.txt', 'r' do |f|
  f.read.each_line do |line|
  name, date = line.split(/,/, 2)
  birth_dates[name] = date.chomp
  birth_dates.each_key { |a| birth_dates[a].strip! }
end

如下：

File.open 'birthdays.txt', 'r' do |f|
  f.read.each_line do |line|
    name, date = line.split(/,/, 2)
    birth_dates[name] = date.chomp.strip
  end
end

或

birth_dates = File.readlines('birthdays.txt').with_object({}) do |line,hsh|
  name, date = line.split(/,/, 2)
  hsh[name] = date.chomp.strip
end

删除Ruby哈希值中的前导空格

2 个答案: