使用Ruby從CSV文件中刪除一行

Question

我已經看到類似的問題，但我想我需要一些更具體的代碼。基本上我從CSV文件中調用了該行，但現在我需要刪除被調用的行。聽起來很簡單，但我在這裏寫信，請求大家幫忙。我知道這裏有很多代碼，但我認爲越多越容易理解上下文。道歉，如果代碼中有太多的噪音。

def delete_user_menu 
    puts "============================================" 
    delete_users_active_list 
    puts " " 
    puts "Please type in the name of the user you wish to eradicate: " 
    print "> " 
    eradicate(gets.chomp) 
end 

def eradicate(delete_input) 
    delete_row = delete_authentication(delete_input) 
    if delete_row 
    puts "Are you sure you want to delete #{delete_input} from the database?" 
    puts "[y]es or [n]o" 
    print "> " 
    delete_answer = gets.chomp 
    if delete_answer == "y" 
     delete_user 
     after_deletion_menu 
    elsif delete_answer == "n" 
     puts "Close call! Taking you back to main menu." 
     sleep 2 
     admin_main_menu 
    else 
     puts "Input not recognised. Please try again." 
     eradicate(delete_input) 
    end 
    else 
    puts "User not recognized. Please try again." 
    sleep 1 
    delete_user_menu 
    end 
end 

def delete_user 
    # this is where the delete user function needs to go 
    after_deletion_menu 
end 

def after_deletion_menu 
    puts " " 
    puts "User deleted! What would you like to do now?" 
    puts "1. Delete another user" 
    puts "2. Back to main menu" 
    print "> " 
    after_deletion_choice = gets.chomp 
    if after_deletion_choice == "1" 
    delete_user_menu 
    elsif after_deletion_choice == "2" 
    admin_main_menu 
    else 
    puts "Input not recognized. Please try again." 
    after_deletion_menu 
    end 
end 

def delete_users_active_list 
    CSV.foreach("./users.csv", headers: true) do |row| 
    username = row['username'] 
    puts "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~" 
    puts "Username: #{username}" 
    end 
end 

def delete_authentication(username) 
    CSV.open('users.csv', headers: true).find { |row| row['username'] == username } 
end 

我看了一下這個問題How to remove a row from a CSV with Ruby 但我不完全理解的答案，因此，爲什麼我在這裏。任何幫助深表感謝。

Answer 1

我看了一下鏈接。首先，他們正在閱讀的整個CSV文件導入table：

table = CSV.table(@csvfile) 

，然後刪除該行從table：最後

table.delete_if do |row| 
    row[:foo] == 'true' 
end 

，他們完全用新的table減去行替換原來的文件：

File.open(@csvfile, 'w') do |f| 
    f.write(table.to_csv) 
end 

這通常是您在處理w時如何做這種操作ith一個文件。它不像數據庫。

編輯 - 在您的情況：

delete_user(delete_input) 
... 
def delete_user(user) 
    ... 
    table.delete_if { |row| row[:username] == user } 
    ...