擅长:python、mysql、java
<p><code>DataFrame.apply</code>和<code>DataFrame.applymap</code>也可以压缩代码:</p>
<pre><code>df=pd.DataFrame({'A':['a','b','c'],'D':['d','e','f'],'G':['g','h','i']})
A D G
0 a d g
1 b e h
2 c f i
</code></pre>
<p>然后:</p>
<pre><code>df.apply(pd.Series.replace,args=('d','ddd')).applymap(str.upper)
A D G
0 A DDD G
1 B E H
2 C F I
</code></pre>
<p>例如,可以通过<code>selection=['A','D']; df[selection]=df[selection].apply(....)</code>来影响和限制某些列。你知道吗</p>