python - 需要解压的值太多(预计为 2 个)[列表]

Question

我有一个包含 4 列的数据集: “日期”、“Num_week”、“日历”

df.head() 看起来像:

    Date    Num_week    Calendar
412 2012-01-01  1      (2012, 1)
413 2012-01-02  2      (2012, 1)
414 2012-01-03  2      (2012, 1)
415 2012-01-04  2      (2012, 1)
416 2012-01-05  2      (2012, 1)

我对列中的值进行排序:sorted(list(set(date_week['calendar'])))

结果:

['(2012, 1)',
 '(2012, 10)',
 '(2012, 11)',
 '(2012, 12)',
 '(2012, 2)',
 '(2012, 3)', etc.

我尝试在循环中分隔年份和月份。

for year, month in list(set(date_week['calendar'])):
    print(year, month)

但是得到 ValueError:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-168-cf01e0d2888e> in <module>()
----> 1 for year, month in list(set(date_week['calendar'])):
      2     print(year, month)

ValueError: too many values to unpack (expected 2)

我已经尝试使用 .items() 并得到错误的结果。

你能帮我解决这个问题吗？

Answer 1

问题是没有元组，而是元组的字符串表示，所以需要先转换:

import ast
date_week['Calendar'] = date_week['Calendar'].apply(ast.literal_eval)

因此可以使用您的解决方案或替代方案:

for year, month in date_week['Calendar'].unique():
    print(year, month)
    2012 1

编辑:替代解决方案 Series.str.findall并转换为元组:

date_week['Calendar'] = date_week['Calendar'].str.findall('\d+').apply(tuple)
print (date_week)
           Date  Num_week   Calendar
412  2012-01-01         1  (2012, 1)
413  2012-01-02         2  (2012, 1)
414  2012-01-03         2  (2012, 1)
415  2012-01-04         2  (2012, 1)
416  2012-01-05         2  (2012, 1)