擅长:python、mysql、java
<pre><code>with open('a.txt', "a+") as f:
f.seek(-2, 2) # Jump to the second last byte.
counter = 0
while counter < 2: # if found EOLS still not enough
if f.read(1) == "\n": # Count EOLs
counter += 1
f.seek(-2, 1) # jump back the read byte plus one more
position = f.tell() # save position
last_three_lines = f.read() # read last three lines
f.seek(position, 0) # jump back
f.truncate() # remove all the rest
f.write(last_three_lines[1:]) # write back necessary stuff
</code></pre>
<h2>输入:</h2>
^{pr2}$
<h2>输出:</h2>
<pre><code>AAAAAa
BBBBBb
CCCCCc
DDDDDd
EEEEE
FFFFFf
GGGGGg
</code></pre>