Python不會重寫第一行使用readlines（）和for循環的文件

Question

我正在Python中編寫一個網頁抓取腳本，它從文本文件的第一行拉出一個'ID'並將其附加到部分URL ;然後從所述URL下載圖像。一切工作正常，但是當我使用第三個函數（它包含下載的實際代碼 - 它工作正常）運行它時，它不會通過刪除第一行來更新文本文件。

我敢肯定，我在這裏失蹤的東西，任何幫助將不勝感激。

def delete_used_id(): 
    # open and save all ids 
    id_file_r = open('C:/Users/my.name/Documents/IDs.txt', 'r') 
    lines = id_file_r.readlines() 
    first_line_unf = str(lines[0])[3:] 
    first_line = first_line_unf.strip() 
    id_file_r.close() 
    # reopen in write mode 
    id_file_w = open('C:/Users/my.name/Documents/IDs.txt','w') 
    for unused_id in lines: 
     if unused_id != first_line: 
      id_file_w.write(unused_id) 
    id_file_w.close() 
    print("Deleting used ID: " + first_line) 

def get_id_from_file(): 
    id_file = open('C:/Users/my.name/Documents/IDs.txt', 'r') 
    # slice the first 3 chars off of the string 
    farmer_id_unf = id_file.readline()[3:] 
    farmer_id = farmer_id_unf.strip() 
    print("Getting Farmer ID: " + farmer_id) 
    return farmer_id 

Answer 1

感謝jonrsharpe和nerdwaller：

答：

def delete_used_id(): 
    # open and save all ids 
    id_file_r = open('C:/Users/my.name/Documents/IDs.txt', 'r') 
    lines = id_file_r.readlines() 
    first_line_unf = lines[0][3:] 
    first_line = first_line_unf.strip() 
    id_file_r.close() 
    # reopen in write mode 
    id_file_w = open('C:/Users/my.name/Documents/IDs.txt','w') 
    for line in lines[1:]: 
     id_file_w.write(line) 
    id_file_w.close() 
    print("Deleting used ID: " + first_line)