python - 对 csv 文件中的每一列进行排序

Question

我有一个包含以下条目的 csv 文件:

    Year,Month,Company A, Company B,Company C, .............Company N
    1990, Jan, 10, 15, 20, , ..........,50
    1990, Feb, 10, 15, 20, , ..........,50

我正在尝试对 A 公司的 csv 文件数据进行排序，依此类推，直到 N 公司。

我的代码在循环中第一次运行时工作正常，但在第二次运行时失败。

    try:
        reader = csv.DictReader(open(self.filename,'r')) #Try and open the file with csv dictreader
    except IOError:
        print "Error Opening File -- Check if file exists"

    ncols = reader.next()
    print ncol.keys()
    for key in ncols.keys():
        if key != 'Month' and key != 'Year':
            print key
            result = sorted(reader, key=lambda d: float(d[key]))
            result = result[-1]
            #print "Year " ,
            print result['Year'],
            #print "Month ",
            print result ['Month'],
            print key,
            print result[key]

输出:

    Company-E
    2008 Oct Company-E 997
    Company-D

    Traceback (most recent call last):
    File "<pyshell#105>", line 1, in <module>
    read.ParseData()
    File "C:/Users/prince/Desktop/CsvRead.py", line 55, in ParseData
    result = result[-1]
    IndexError: list index out of range

Answer 1

我建议使用 pandas :

import pandas
df = pandas.read_csv(filename)
for col in df.columns:
    if col != 'Month' and col != 'Year':
        df = df.sort(col)
df.to_csv(out_filename, index=False)