Python在文件中找到最后一次出现

时间:2015-06-05 13:04:58

标签: python dictionary last-occurrence

我有一个不同IP的文件。

192.168.11.2
192.1268.11.3
192.168.11.3
192.168.11.3
192.168.11.2
192.168.11.5

这是我的代码,直到现在。我打印IP和出现的地方,但是我怎样才能知道每个IP的最后一次出现的时间。这是一种简单的方法吗?

liste = []

dit = {}
file = open('ip.txt','r')

file = file.readlines()

for line in file:
        liste.append(line.strip())

for element in liste:
        if element in dit:
                dit[element] +=1
        else:
                dit[element] = 1

for key,value in dit.items():
        print "%s occurs %s times, last occurence at line"  %(key,value)

输出:

192.1268.11.3 occurs 1 times, last occurence at line
192.168.11.3 occurs 2 times, last occurence at line
192.168.11.2 occurs 2 times, last occurence at line
192.168.11.5 occurs 1 times, last occurence at line

5 个答案:

答案 0 :(得分:3)

试试这个:

liste = []

dit = {}
file = open('ip.txt','r')

file = file.readlines()

for line in file:
        liste.append(line.strip())

for i, element in enumerate(liste, 1):
        if element in dit:
                dit[element][0] += 1
                dit[element][1] =  i
        else:
                dit[element] = [1,i]

for key,value in dit.items():
        print "%s occurs %d times, last occurence at line %d" % (key, value[0], value[1])

答案 1 :(得分:2)

这是一个解决方案:

from collections import Counter

with open('ip.txt') as input_file:
    lines = input_file.read().splitlines()

    # Find last occurrence, count
    last_line = dict((ip, line_number) for line_number, ip in enumerate(lines, 1))
    ip_count = Counter(lines)

    # Print the stat, sorted by last occurrence
    for ip in sorted(last_line, key=lambda k: last_line[k]):
        print '{} occurs {} times, last occurence at line {}'.format(
            ip, ip_count[ip], last_line[ip])            

讨论

  • 我使用enumerate函数生成行号(从第1行开始)
  • 使用(ip,line_number)序列,可以轻松生成字典last_line,其中键是IP地址,值是最后一行。
  • 要计算出现次数,我使用Counter类 - 非常简单
  • 如果您希望报告按IP地址排序,请使用sorted(last_line)
  • 此解决方案具有性能影响:它会扫描IP列表两次:一次计算last_line,一次计算ip_count。这意味着如果文件很大,这个解决方案可能并不理想

答案 2 :(得分:1)

last_line_occurrence = {}
for element, line_number in zip(liste, range(1, len(liste)+1)):
     if element in dit:
            dit[element] +=1
     else:
            dit[element] = 1
     last_line_occurrence[element] = line_number

for key,value in dit.items():
     print "%s occurs %s times, last occurence at line %s"  %(key,value, last_line_occurrence[key])

答案 3 :(得分:1)

这可以在一次通过中轻松完成,而无需将所有文件读入内存:

from collections import defaultdict
d = defaultdict(lambda: {"ind":0,"count":0})

with open("in.txt") as f:
    for ind, line in enumerate(f,1):
        ip = line.rstrip()
        d[ip]["ind"] = ind
        d[ip]["count"]  += 1

for ip ,v in d.items():
    print("IP {}  appears {} time(s) and the last occurrence is at  line {}".format(ip,v["count"],v["ind"]))

输出:

IP 192.1268.11.3  appears 1 time(s) and the last occurrence is at line 2
IP 192.168.11.3  appears 2 time(s) and the last occurrence is at line 4
IP 192.168.11.2  appears 2 time(s) and the last occurrence is at line 5
IP 192.168.11.5  appears 1 time(s) and the last occurrence is at line 6

如果您想要首次遇到ip的订单,请使用OrderedDict:

from collections import OrderedDict
od = OrderedDict()
with open("in.txt") as f:
    for ind, line in enumerate(f,1):
        ip = line.rstrip()
        od.setdefault(ip, {"ind": 0,"count":0})
        od[ip]["ind"] = ind
        od[ip]["count"] += 1

for ip ,v in od.items():
    print("IP {}  appears {} time(s) and the last occurrence is at  line {}".format(ip,v["count"],v["ind"]))

输出:

IP 192.168.11.2  appears 2 time(s) and the last occurrence is at line 5
IP 192.1268.11.3  appears 1 time(s) and the last occurrence is at line 2
IP 192.168.11.3  appears 2 time(s) and the last occurrence is at line 4
IP 192.168.11.5  appears 1 time(s) and the last occurrence is at line 6

答案 4 :(得分:0)

您可以使用其他词典。在此词典中,您为每一行存储最后一次出现的行号,并在每次找到另一次出现时覆盖。最后,在这个词典中,对于每一行,您将获得最后一次出现的行号。

显然,您需要为每条读取行增加一个计数器,以便知道您正在阅读的行。