在Python中添加文件末尾的東西？

Question

我只是想添加一個字符串到文件結尾，但我無法讓它工作。我得到這個錯誤：

IOError: (9, 'Bad file descriptor') 

我得到它的行123這是在下面的代碼，但標有#hashcomment：

pluginlokacija2 = os.path.realpath("%s/plugins"%os.getcwd()) 
fo = open("%s/TwistedJobs/config.yml"%pluginlokacija2, "wb") 
old = fo.read() #this is line no. 123 
fo.seek(0) 
fo.write("%s\n- %s\n " % (old, event.getPlayer().getName())) 
fo.close 

在此先感謝，阿馬爾！

P.S.如果您需要更多信息，請在評論中提出要求！

Answer 1

您需要打開文件，以便使用.read()

你只打開了它與"wb"寫讀書。

使用"rb"讀，"wb"寫，和"ab"追加

添加'+'像"ab+"允許simulaneous讀取和附加/寫入

有不同模式的基準here

示例：

with open("filepath/file.ext", "ab+") as fo: 
    old = fo.read() # this auto closes the file after reading, which is a good practice 
    fo.write("something") # to the end of the file 

Answer 2

你想open(filename, "ab+")：

The mode can be 'r', 'w' or 'a' for reading (default), writing or appending. The file will be created if it doesn't exist when opened for writing or appending; it will be truncated when opened for writing. Add a 'b' to the mode for binary files. Add a '+' to the mode to allow simultaneous reading and writing.

與「追加」模式下，你甚至不必閱讀現有的內容，尋求

而且（0）等，你可以只是簡單的寫：

bruno@betty ~/Work/playground $ cat yadda.txt 
foo 
bar 
bruno@betty ~/Work/playground $ python 
Python 2.7.3 (default, Apr 10 2013, 06:20:15) 
[GCC 4.6.3] on linux2 
Type "help", "copyright", "credits" or "license" for more information. 
>>> f = open("yadda.txt", "a+") 
>>> f.write("newline here\n") 
>>> f.close() 
>>> 
bruno@betty ~/Work/playground $ cat yadda.txt 
foo 
bar 
newline here 
bruno@betty ~/Work/playground $