擅长:python、mysql、java
<p>其他人都已经提到了pep,但也要注意在关键代码中间不要有import语句。至少在Python2.6下,当函数有import语句时,还需要几个字节码指令。</p>
<pre><code>>>> def f():
from time import time
print time()
>>> dis.dis(f)
2 0 LOAD_CONST 1 (-1)
3 LOAD_CONST 2 (('time',))
6 IMPORT_NAME 0 (time)
9 IMPORT_FROM 0 (time)
12 STORE_FAST 0 (time)
15 POP_TOP
3 16 LOAD_FAST 0 (time)
19 CALL_FUNCTION 0
22 PRINT_ITEM
23 PRINT_NEWLINE
24 LOAD_CONST 0 (None)
27 RETURN_VALUE
>>> def g():
print time()
>>> dis.dis(g)
2 0 LOAD_GLOBAL 0 (time)
3 CALL_FUNCTION 0
6 PRINT_ITEM
7 PRINT_NEWLINE
8 LOAD_CONST 0 (None)
11 RETURN_VALUE
</code></pre>