Python帮助 | 从底部读取文本文件数据

Question

Python帮助 | 从底部读取文本文件数据

3

有人能够看一下我的程序吗？有一个错误我无法识别，真的让我很困惑。同时，请解释一下问题，以便我可以理解如何在其他情况下使用该函数和程序。

input_name = input("\nPlease enter students name » ").strip()
datafile = '1.txt'

while open(datafile, 'r') as f:
    data = {}
    for line in f:
        name, value = line.split('=')
        name = name.strip
        value = str(value)
        data.setdefault(name, []).append(value)
else:
    break
avg = {}
for name, scores in data.items():
    last_scores = scores[-3:]
    avg[name] = sum(last_scores) / len(last_scores)

print("\n", input_name,"'s average score is", avg(input_name))

- GameFederer

4个回答

0

希望这有所帮助：

with open('demo.txt','r') as f:
    reversedList=reversed(f.read().splitlines())
    print filter(lambda x:'Tanzil' in x,reversedList)[:3]

输出：

['Tanzil = 3', 'Tanzil = 5', 'Tanzil = 10']

- Ahsanul Haque

我不仅仅想要它用于“tanzil”，我想要它用于任何输入到变量“name”下的名称。 - GameFederer

它适用于任何变量。只需用“'Tanzil'”替换变量名称即可。您可以创建一个接受名称并返回列表的函数。 - Ahsanul Haque

0

我想以下内容会帮助您完成任务：

将计数器和总和初始化为0，并以倒序读取文件
拆分行并检查第一部分是否为所需名称。如果是，则获取第二部分，将其添加到总和中并增加计数器
当计数器达到3时，退出循环

将总和除以3后打印平均值

counter, sumTotal = 0, 0
for line in reversed(open("1.txt").readlines()):
  splitArray = line.split("=")
  if splitArray[0].strip() == name:
    sumTotal = sumTotal + int(splitArray[1].strip())
    counter = counter + 1
  if counter == 3:
    break

if counter == 3:
  print "Average for {0} = {1}".format(name, sumTotal/3)
else if counter == 0:
  print "Name {0} not found".format(name)
else:
  print "Name {0} does not have three scores".format(name)

- Matt

0

如果你在Linux系统上，可以使用tac命令（cat的倒序） - 将文件反向连接并打印。

>>> import os
>>> for line in os.popen('tac 1.txt'):
...  do you existing processing here

- Rolf of Saxony

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Mike Müller · Accepted Answer

单步操作

将所有数据读入字典中：

data = {}
for line in f:
    name, value = line.split('=')
    name = name.strip()
    value = int(value)
    data.setdefault(name, []).append(value)

< p > data 的内容：

{'Chris': [9, 9],
 'John': [6, 4, 5],
 'Sarah': [4, 7],
 'Tanzil': [4, 4, 10, 5, 3],
 'Tom': [2]}

现在您可以计算平均值：

last_scores = data['Tanzil'][-3:]
avg = sum(last_scores) / len(last_scores)


>>> avg
6.0

或者对所有人求平均值：

avg = {}
for name, scores in data.items():
    last_scores = scores[-3:]
    avg[name] = sum(last_scores) / len(last_scores)

现在avg的值为:

{'Chris': 9.0, 'John': 5.0, 'Sarah': 5.5, 'Tanzil': 6.0, 'Tom': 2.0}

显示所有结果：

for name, value in avg.items():
    print(name, value)

打印：

Tanzil 6.0
Chris 9.0
Sarah 5.5
John 5.0
Tom 2.0

或按平均分从高到低排序：

from operator import  itemgetter

for name, value in sorted(avg.items(), key=itemgetter(1), reverse=True):
        print(name, value)

打印：

Chris 9.0
Tanzil 6.0
Sarah 5.5
John 5.0
Tom 2.0

完整程序

input_name = input("\nPlease enter students name » ").strip()
datafile = '1.txt'

with open(datafile, 'r') as f:
    data = {}
    for line in f:
        name, value = line.split('=')
        name = name.strip()
        value = int(value)
        data.setdefault(name, []).append(value)

avg = {}
for name, scores in data.items():
    last_scores = scores[-3:]
    avg[name] = sum(last_scores) / len(last_scores)

print("\n", input_name,"'s average score is", avg[input_name])