python中time.time()和 time.strftime()：
time.time()返回的是一个浮点数，以秒为单位，time.strftime后可以自定义格式，如time.strftime('%Y-%m-%d %H:%M:%S')
vi a1.py
#!/usr/bin/python
import time
t1 = time.time() print t1
t2 = time.strftime('%Y-%m-%d %H:%M:%S') print t2 :wq
python a1.py
今天、昨天、上月、去年：
vi a2.py
#!/usr/bin/python
import time today = time.strftime('%Y-%m-%d') yesterday = time.localtime()[2]-1 last_month = time.localtime()[1]-1 last_year = time.localtime()[0]-1 print today print yesterday print last_month print last_year :wq
