'打開（）'不起作用？

Question

我的代碼：

filename = "C:/users/patrik/documents/mypython.txt" 
with open(filename) as f: 
    if f.readlines()[0] == "patrik's file": #first line 
     f.write("This file has been read by patrik!") 

爲什麼它不工作？我沒有收到任何錯誤，此後文件內容變得雜亂，我做錯了什麼？

Answer 1

要執行讀取和寫文件操作就可以選擇這些模式之一：

'r+'：

Opens a file for both reading and writing. The file pointer will be at the beginning of the file.

'a+'：

Opens a file for both appending and reading. The file pointer is at the end of the file if the file exists. The file opens in the append mode. If the file does not exist, it creates a new file for reading and writing.

注意file是一個內嵌函數在python中，所以你不應該用它作爲變量名稱