ruby - 以类似表格的格式输出散列

Question

我需要将哈希值输出到表中。数据有一个名为 students 的数组，它的散列键为 "first_name"、"last_name" 和 "grade_level".

这是我的代码。

students = []

# Dummy Inputs.
students = [
  {
      "first_name" => "Bob",
      "last_name" => "Builder",
      "grade_level" => 4
      },
  {
      "first_name" => "Test",
      "last_name" => "Buida",
      "grade_level" => 3
      },
  {
      "first_name" => "Senior",
      "last_name" => "June",
      "grade_level" => 5
      },
  {
      "first_name" => "John",
      "last_name" => "Smith",
      "grade_level" => 2
      },
  {
      "first_name" => "Me",
      "last_name" => "Developer",
      "grade_level" => 11
      }]

...

puts "\n--------------- \n" +
          "| CLASS ROSTER \n" +
          "--------------- \n"  # Felt lazy to add them individual put
    puts "First Name    Last Name    Grade Level\n"

    students.each do |student|
      puts "#{student["first_name"]}        #{student["last_name"]}     #{student["grade_level"]}"

我用tab来设置列。有时，它会出现如下故障。

有什么办法可以让它变得更好吗？

Answer 1

一个人可能应该利用 String#ljust和 String#rjust这里有 helper 。

首先，让我们准备输出:

FIELD_SIZE = 20
roster =
  students.map do |s|
    s.values.map do |f|
      f.to_s.ljust(FIELD_SIZE) # 1 row
    end.join('   ')            # join columns with spaces
  end.join($/)                 # join rows with OS-dependent CR/LF
titles =
  ['First Name', 'Last Name', 'Grade Level'].map do |t|
    t.to_s.ljust(FIELD_SIZE)
  end.join(' | ')              # join with bars

现在你可以打印它了:

puts titles, roster

这是输出:

First Name           | Last Name            | Grade Level         
Bob                    Builder                4                   
Test                   Buida                  3                   
Senior                 June                   5                   
John                   Smith                  2                   
Me                     Developer              11   

随意更改连接器和字段大小以查看其工作原理。