python 常用操作

python 常用操作

1. 读取文件

fd = open(file)
for i in fd.read().split('
'):
    print i

或者

fp = open('test.txt', 'r')
while True:
    line = fp.readline().strip() #去掉后面的回车
    if line:
        print line

打开文件覆盖写

fd_pre = open(PRE_FILE, "w+")
if not fd_pre.read():
    fd_pre.write('tes11
')
else:
    fd_pre.write('tes11
')

2. 字典删除一个key

>>> dic = dict()
>>> dic['k1'] = 'v1'
>>> dic['k2'] = 'v2'
>>> dic
{'k2': 'v2', 'k1': 'v1'}
>>> del dic['k1']
>>> dic
{'k2': 'v2'}

3. 获取参数

from optparse import OptionParser, OptionGroup
def parse_argv(argv = sys.argv[1:])
    parser = OptionParser(usage = 'Usage: python %prog [options]',
                          version = '%prog v0.1, release version',
                          description = "DESC: %prog operatrion")
    parser.add_option('-s', '--source',
                      dest = 'source',
                      help = "source")
    parser.add_option('-k', '--keyword',
                      dest = 'keyword',
                      help = "source")
    parser.add_option('-t', '--target',
                      dest = 'target',
                      help = "target")

    (options, args) = parser.parse_args(argv)
    if not options.source or not options.keyword or not options.target:
        parser.print_help()
        sys.exit(1)

    return (options, args)

4. 将字符串转化为时间

>>> import datetime
>>> a = '2016-02-03  04:02:37'
>>> datetime.datetime.strptime(a, "%Y-%m-%d %H:%M:%S")
datetime.datetime(2016, 2, 3, 4, 2, 37)

5. python时间比较

6. python获取标准时间

>>> import time
>>> time.strftime("%Y-%m-%d %X", time.localtime(time.time()))

>>> import datetime