Question

我的代码：

infile = open("ALE.txt", "r")
outfile = open("ALE_sorted.txt", "w")

for line in infile:
    data = line.strip().split(',')
    wins = int(data[2])
    percentage = 162 / wins
    p = str(data[0]) + ", " + data[1] + ", " + data[2] + ", " + 
str(round(percentage, 3)) + "\n"
    outfile.write(p)
infile.close()
outfile.close()

原始的infile（“ALE.txt”）只是下面的前三列。从上面的代码输出的文本文件如下所示：

巴尔的摩，93,69,2.348 波士顿，69,93,1.742
纽约，95,67,2.418
坦帕湾，90,72,2.25 多伦多，73,89,1.82

我知道代码正确计算了胜率（第2列/总胜数），但我想按第4列（胜率）对此列表进行排序。

Answer 1

将您的数据附加到列表中，例如d。

使用列表的第三项（第4列）对其进行排序。参考 - operator.itemgetter

将已排序的数据写入输出文件。

输入文件的内容

[kiran@localhost ~]$ cat infile.txt
Baltimore, 93, 69
Boston, 69, 93
New York, 95, 67
Tampa Bay, 90, 72
Toronto, 73, 89

<强>代码::

>>> from operator import itemgetter
>>> d=[]
>>> with open('infile.txt','r') as infile:
...     for line in infile.readlines():
...             data = line.strip().split(',')
...             wins = int(data[2])
...             percentage = 162 / float(wins)
...             data.append(str(round(percentage, 3))) #add percentage to your list that already contains the name and two scores.
...             d.append(data) # add the line to a list `d`
...
>>> print d
[['Baltimore', ' 93', ' 69', '2.348'], ['Boston', ' 69', ' 93', '1.742'], ['New York', ' 95', ' 67', '2.418'], ['Tampa Bay', ' 90', ' 72', '2.25'], ['Toronto', ' 73', ' 89', '1.82']]
>>> d.sort(key=itemgetter(3)) #sort the list `d` with the third item(4th column) of your sublist.
>>> print d
[['Boston', ' 69', ' 93', '1.742'], ['Toronto', ' 73', ' 89', '1.82'], ['Tampa Bay', ' 90', ' 72', '2.25'], ['Baltimore', ' 93', ' 69', '2.348'], ['New York', ' 95', ' 67', '2.418']]
>>> #write the items in list d to your output file
>>>
>>> with open('outfile.txt','w') as outfile:
...     for line in d:
...             outfile.write(','.join(line)+'\n')
...
>>>

输出文件的内容：

[kiran@localhost ~]$ cat outfile.txt
Boston, 69, 93,1.742
Toronto, 73, 89,1.82
Tampa Bay, 90, 72,2.25
Baltimore, 93, 69,2.348
New York, 95, 67,2.418

Answer 2

试试这个：

infile  = open("ALE.txt", "r")
outfile = open("ALE_sorted.txt", "w")

master_data = []

# Load in data from the infile and calculate the win percentage.
for line in infile:

    data = line.strip().split(', ')

    wins = int(data[2])
    percentage = 162 / wins
    data.append(str(round(percentage, 3)))

    master_data.append(data)

# Sort by the last column in reverse order by value and store the 
# sorted values and original indices in a list of tuples.
sorted_column = sorted([(float(data[-1]), index) for index, data in \
                        enumerate(master_data)], reverse = True)

# Reassign master_data according to the sorted positions.
master_data   = [master_data[data[1]] for data in sorted_column]

# Write each line to the outfile.
for data in master_data:

    outfile.write(str(", ".join(data) + "\n"))

infile.close()
outfile.close()

infile的内容如下：

Baltimore, 93, 69
Boston, 69, 93
New York, 95, 67
Tampa Bay, 90, 72
Toronto, 73, 89

结果outfile包含以下内容：按从最高到最低的新生成的第四列的值排序：

New York, 95, 67, 2.418
Baltimore, 93, 69, 2.348
Tampa Bay, 90, 72, 2.25
Toronto, 73, 89, 1.82
Boston, 69, 93, 1.742

Answer 3

首先，处理此问题时，最好使用line.split（＆＃39;，＆＃39;）。strip（）。

import csv
with open('ALE.txt', 'r') as infile:
    reader = csv.reader(infile)
    data = []
    for line in reader:
        formatted_line = [i.strip() for i in line]
        wins = int(formatted_line[2])
        percentage = 100*wins/total_wins
        formatted_line.append(str(round(percentage,3)))
        data.append(formatted_line)
    data = sorted(p, lambda x: x[3])
with open('ALE_sorted.txt', 'w', newline='') as outfile:
    writer = csv.writer(outfile)
    writer.writerows(data)

Answer 4

排序第4列的最佳方法是使用pandas打开文件。这是如何做到的：

import pandas as pd

outfile=pd.read_csv("ALE_sorted.txt")
column=outfile.columns.values.tolist()  # will give you the name of your column

#It will return [0L,1L,2L,3L] where 3L is your fourth column and refers to a long int.

outfile.sort_values(by=[3L])

print(outfile.3L)  # to see the sorted column

这将产生：

我如何按第n列对输出的文本文件进行排序 - Python

4 个答案: