小编fir*_*442的帖子

Git有各种读/写内部数据库的操作.我已经读过Git中的写操作是原子的.但是,对于读取等其他操作,哪些操作会锁定数据库？

具体来说,我正在编写一个同时调用"git blame"的应用程序,我想确保这是我可以多线程的东西.

我正在尝试使用Python Twisted - UDP示例来使用UDP广播.我可以从客户端发送消息并在服务器上接收它,但是,它不会发回消息.

客户:

from twisted.internet.protocol import DatagramProtocol
from twisted.internet import reactor

from socket import SOL_SOCKET, SO_BROADCAST

class EchoClientDatagramProtocol(DatagramProtocol):
    strings = [
        "Hello, world!",
        "What a fine day it is.",
        "Bye-bye!"
    ]

    def startProtocol(self):
        self.transport.socket.setsockopt(SOL_SOCKET, SO_BROADCAST, True)
        self.transport.connect("255.255.255.255", 8000)
        self.sendDatagram()

    def sendDatagram(self):
        if len(self.strings):
            datagram = self.strings.pop(0)
            self.transport.write(datagram)
        else:
            reactor.stop()

    def datagramReceived(self, datagram, host):
        print 'Datagram received: ', repr(datagram)
        self.sendDatagram()

def main():
    protocol = EchoClientDatagramProtocol()
    #0 means any port
    t = reactor.listenUDP(0, protocol)
    reactor.run()

if __name__ == …

我在R中有以下最小例子:

testing = data.frame(c("Once a week", "Once a week", "Rarely", "Once a month", "Once a month"), c("Once a month", "Once a month", "Once a week", "Rarely", "Rarely"))
colnames(testing) = c("one", "two")
testing

        one          two
1  Once a week Once a month
2  Once a week Once a month
3       Rarely  Once a week
4 Once a month       Rarely
5 Once a month       Rarely

我希望最终结果是一个数据框,其中列中包含所有可能的分类因子,其余列是每个列/变量的计数,如下所示:

categories    one    two
Rarely        1      2
Once a month  2      2
Once a week   2      1 …