使用 Python 脚本每小时将时间戳写入文件

编写了一个 Python 脚本，该脚本不断从 Twitter 抓取数据并将其写入文件。希望该程序在每小时写入当前时间戳到文件中。代码如下所示：

#! /usr/bin/env python
import tweetstream
import simplejson
import urllib
import time
import datetime
import sched

class twit: 
    def __init__(self,uname,pswd,filepath):
        self.uname=uname
        self.password=pswd
        self.filepath=open(filepath,"wb")

    def main(self):
        i=0
        s = sched.scheduler(time.time, time.sleep)
        output=self.filepath

        #Grab every tweet using Streaming API
        with tweetstream.TweetStream(self.uname, self.password) as stream:
            for tweet in stream:
                if tweet.has_key("text"):
                    try:
                        #Write tweet to file and print it to STDOUT
                        message=tweet['text']+ "\n"
                        output.write(message)
                        print tweet['user']['screen_name'] + ": " + tweet['text'], "\n"

                        ################################
                        #Timestamp code
                        #Timestamps should be placed once every hour
                        s.enter(10, 1, t.timestamp, (s,))
                        s.run()
                    except KeyError:
                        pass
    def timestamp(self,sc):
        now = datetime.datetime.now()
        current_time= now.strftime("%Y-%m-%d %H:%M")
        print current_time
        self.filepath.write(current_time+"\n")


if __name__=='__main__':
    t=twit("rohanbk","cookie","tweets.txt")
    t.main()

2、解决方案

为了解决这个问题，可以修改代码，使用 sched.scheduler() 模块来安排一次性任务。以下是修改后的代码：

import tweetstream
import simplejson
import urllib
import time
import datetime
import sched

class twit: 
    def __init__(self,uname,pswd,filepath):
        self.uname=uname
        self.password=pswd
        self.filepath=open(filepath,"wb")

    def main(self):
        i=0
        s = sched.scheduler(time.time, time.sleep)
        output=self.filepath

        #Grab every tweet using Streaming API
        with tweetstream.TweetStream(self.uname, self.password) as stream:
            for tweet in stream:
                if tweet.has_key("text"):
                    try:
                        #Write tweet to file and print it to STDOUT
                        message=tweet['text']+ "\n"
                        output.write(message)
                        print tweet['user']['screen_name'] + ": " + tweet['text'], "\n"

                        ################################
                        #Timestamp code
                        #Timestamps should be placed once every hour
                        s.enter(3600, 1, self.timestamp, (s,))
                        s.run()
                    except KeyError:
                        pass
    def timestamp(self,sc):
        now = datetime.datetime.now()
        current_time= now.strftime("%Y-%m-%d %H:%M")
        print current_time
        self.filepath.write(current_time+"\n")


if __name__=='__main__':
    t=twit("rohanbk","cookie","tweets.txt")
    t.main()

在该代码中，使用 s.enter(3600, 1, self.timestamp, (s,)) 函数安排每小时运行一次 timestamp() 函数。这样，就可以每小时将时间戳写入文件，而无需不断检查时间。