求大佬解答，问题再最后一行，如果我想用dump给文件追加内容该怎么办

G-Bule

'123'
>>> # 我这里设置了三个变量
>>> a
123
>>> b
[1, 2, 3]
>>> b
[1, 2, 3]
>>> # 将a,b两个变量储存
>>> with open(r"E:\我python\test.txt","wb") as f:
        pickle.dump((a,b),f)

       
>>> # 再拿出来是没问题的
>>> with open(r"E:\我python\test.txt","rb") as f:
        pickle.load(f)

       
(123, [1, 2, 3])
>>> with open(r"E:\我python\test.txt","rb") as f:
        pickle.load(f)

       
(123, [1, 2, 3])
>>> # 同样的运行两次，发现里面的数据不会因为拿出来而消失
>>> # 这时我想往里面追加变量c
>>> with open(r"E:\我python\test.txt","r+b") as f: # 采用的是r+b的二进制读写打开
        pickle.dump(c,f)

       
>>> # 再次拿出来看看
>>> with open(r"E:\我python\test.txt","r+b") as f: # 还是二进制读写
        pickle.load(f)

       
'123'
>>> # 晕，怎么变成只有变量c了，和单独的“w”打开出现的截断一样，求解答

G-Bule

>>> # 还是这三个变量
>>> a
123
>>> b
[1, 2, 3]
>>> c
'123'
>>> with open(r"E:\我python\test.txt","wb") as f:
        pickle.dump((a,b),f)

       
>>> with open(r"E:\我python\test.txt","ab") as f: # 这次采用ab来打开，给文件追加c
        pickle.dump(c,f)

       
>>> # 再把数据拿出来看看
>>> with open(r"E:\我python\test.txt","rb") as f:
        pickle.load(f)

       
(123, [1, 2, 3])
>>> # 诶，变量c怎么不见了，又晕了，求解答

jackz007

          pickle 的 dump 用于对对象的现场整体保存以及恢复，是一张现场快照，只适合一次性保存和使用，不适合追加以及做任何的加工和修改。