>>>A = [1,2,3,4] >>>isinstance(A, list)
(2) sort, reverse 以及 sorted, reversed
A=[3,1,2] assert(A.sort() == sorted(A)) assert(A.reverse() == reversed(A))
(3) 一个简单的命令行progress bar:
def progress_bar(current, total, width=20):
i = int (current*width/total)
sys.stdout.write("\r|" + '*'*i + ' '*(width-i)+"|")
(4) PyYaml最简单的用法
- 把一个变量A dump到一个文件f中
A = {1:'a', 2:'b'} yaml.dump(A, f)
- 从外部yaml文件文件load出数据到A
A=yaml.load(filehandler)
(5) 读取命令行的输入：
input(prompt)
raw_input(prompt)
import getpass getpass.getpass(prompt)
(6) 使用re正则表达式
import re >>>m = re.match(r"(\d+)\s*(M|K)(bit|Byte)", "1024Mbit") >>>print m.group(1), m.group(2)+m.group(3) 1024 Mbit
还可以使用(?P
m = re.match(r"(?P\d+)\s*(M|K)(bit|Byte)", "1024Mbit") >>>print m.group("num"), m.group(2)+m.group(3) 1024 Mbit
为了提高使用正则表达式的效率, 可以先编译正则表达式, 然后每次用编译出来的正则字符串去匹配
>>>p = re.compile(r"(\d+)\s*(M|K)(bit|Byte)")
>>>g = p.match("1024Mbit")
>>>print g.group(1), g.group(2)+g.group(3)
1024 Mbit
(7)显示异常的类型和错误信息
try:
do what you want
except:
print sys.exc_info()[0], sys.exc_info()[1]sys.exc_info()[0]: 异常的类型sys.exc_info()[1]: 异常的信息
(8) Python 2.5以后支持with 语句. 用在file object上,就不用close这个文件了
with open("max_load_vs_k.dat","w") as f:
do some file operation with f(9)Python Search Path
>>>sys.path ['', '/Library/Python/2.6/site-packages/ipython-0.10.1-py2.6.egg', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python26.zip', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-darwin', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-mac', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-mac/lib-scriptpackages', '/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-tk', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-old', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-dynload', '/Library/Python/2.6/site-packages', '/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/PyObjC', '/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/wx-2.8-mac-unicode']
