写入和读取文件时的奇怪行为 [英] Weird behavior when writing and reading file

问题描述

当执行以下代码时，在第二次读取后，文件被零填充，直到达到 4096 字节大.我不明白为什么:

When executing the following code, after the second read, file gets filled with zero until being 4096 bytes large. I can't figure out why :

f = open("file.txt", "w+")
f.read()
# gives ''
f.write("Hello")
f.read()
# filled with \x00,\x00
f.close()
# file is 4096 bytes large...

推荐答案

解决问题的最佳方式:不要混合使用 read() 和 write().

Best way to solve your problem: don't mix read() and write().

否则:在 write() 之后，在第二个 read() 之前使用 seek() 来读取您的文件 开始:

Otherwise: after the write(), use seek() before the second read() to read your file from the beginning:

f = open("file.txt", "w+")
print f.read()      # prints ''
f.write("Hello")
f.seek(0)
print f.read()      # print 'Hello'
f.close()

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