每次代码运行时如何在python中只创建一个对象

Question

每次我运行此代码。 Tracker类在输入文本文件的每一个新行上创建一个新对象。我想在你第一次运行代码时只创建一个对象，并在整个输入文件中继续使用该对象，而不是每次调用我的类时都不创建新对象。

class Tracker(object):

    def __init__(self,region):
        self.region = region

    def make_tracker(self):
        self.region = re.search(r'CLI Command: \'show card detail\'',line)
        if self.region:
            print line
            self.region = "CPM OR IOM"
            return self.region
        end = re.search(r'(SUN|MON|TUE|WED|THU|FRI|SAT)(.*)(\d)(\d)(\d)(\d) UTC:$',line)
        if end:
            flag = "end"
            return flag

with open ('/home/thamer/SAMPLE.TXT','r') as f:
    for line in f:    
        first = Tracker(line)
        region = first.make_tracker()

        if region =="CPM or IOM":
            print "CPM or IOM"

Answer 1

您应该将with语句更改为以下内容：

with open ('/home/thamer/SAMPLE.TXT','r') as f:
    tracker = Tracker("")
    for line in f:    
        tracker.region = line
        region = tracker.make_tracker()

        if region =="CPM or IOM":
            print "CPM or IOM"

这样，您每次都会更改tracker.region而不是tracker。