擅长:python、mysql、java
<p>默认情况下,遍历文件会逐行检索数据。您可以使用<a href="http://docs.python.org/3/library/functions.html#iter" rel="nofollow noreferrer">^{<cd1>}</a>内置函数的两个参数以字节流的形式读入文件,如下所示。注意,这种方法将<em>而不是</em>一次将整个文件读入内存,就像使用<a href="https://docs.python.org/3/library/io.html#io.IOBase.readlines" rel="nofollow noreferrer">^{<cd2>}</a>内置程序那样。你知道吗</p>
<pre><code>KEY = 4
encoded = ""
with open("mytext.txt", 'rb') as my_text:
# Using iter() like below causes it to quit when read() returns an
# empty char string (which indicates the end of the file has been
# reached).
for c in iter(lambda: my_text.read(1), b''):
rem = (ord(c) - 97 + KEY) % 26
encoded += chr(rem + 97)
print(encoded)
</code></pre>