python之打印日志logging

 import logging

 # 简单打印日志举例
 logging.basicConfig(level=logging.DEBUG)  # 设置日志级别，WARN
 logging.warning('Watch out!')  # will print a message to the console
 logging.info('I told you so')  # will not print anything

 # 打印日志到文件,注意要新起一个文件，否则不能保存文件
 def log_to_file(logs_dir="D:\\test_data\\logs\\log_DEBUG.txt"):
     logging.basicConfig(filename=logs_dir, level=logging.DEBUG)
     logging.debug('This message should go to the log file')
     logging.info('So should this')
     logging.warning('And this, too')

 log_to_file()

 # 多参数日志
 logging.warning('%s before you %s', 'Look', 'leap!')

 # 日志中打印时间
 logging.basicConfig(format='%(asctime)s %(message)s')
 logging.warning('is when this event was logged.')

 # 指定时间格式
 logging.basicConfig(format='%(asctime)s %(message)s', datefmt='%Y-%m-%d %I:%M:%S %p')
 logging.warning('is when this event was logged.')

注意：logging的参数设置只在第一次运行之前有效，只能设置一次，后续设置无效。

指定时间格式运行结果：

 # 指定时间格式
 2017-08-12 10:47:07 PM is when this event was logged.