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python - TypeError：“NoneType”和“float”的实例之间不支持“<”

问题描述

我正在关注 YouTube 教程，我从教程中编写了这段代码

import numpy as np
import pandas as pd
from scipy.stats import percentileofscore as score

my_columns = [
  'Ticker', 
  'Price', 
  'Number of Shares to Buy', 
  'One-Year Price Return',
  'One-Year Percentile Return',
  'Six-Month Price Return',
  'Six-Month Percentile Return',
  'Three-Month Price Return',
  'Three-Month Percentile Return',
  'One-Month Price Return',
  'One-Month Percentile Return'
  ]
final_df = pd.DataFrame(columns = my_columns)
# populate final_df here....
pd.set_option('display.max_columns', None)
print(final_df[:1])
time_periods = ['One-Year', 'Six-Month', 'Three-Month', 'One-Month']    
for row in final_df.index:
  for time_period in time_periods:
    change_col = f'{time_period} Price Return'
    print(type(final_df[change_col])) 
    percentile_col = f'{time_period} Percentile Return'
    print(final_df.loc[row, change_col])
    final_df.loc[row, percentile_col] = score(final_df[change_col], final_df.loc[row, change_col])
print(final_df)

它将我的数据框打印为

| Ticker |  Price  | Number of Shares to Buy | One-Year Price Return  | One-Year Percentile Return | Six-Month Price Return | Six-Month Percentile Return | Three-Month Price Return | Three-Month Percentile Return | One-Month Price Return  | One-Month Percentile Return  |
|--------|---------|-------------------------|------------------------|----------------------------|------------------------|-----------------------------|--------------------------|-------------------------------|-------------------------|------------------------------|
| A      |  120.38 | N/A                     | 0.437579               | N/A                        | 0.280969               | N/A                         | 0.198355                 | N/A                           | 0.0455988               |             N/A              |

但是当我调用 score 函数时，我得到了这个错误

<class 'pandas.core.series.Series'>
0.4320217937551543
Traceback (most recent call last):
  File "program.py", line 72, in <module>
    final_df.loc[row, percentile_col] = score(final_df[change_col], final_df.loc[row, change_col])
  File "/Users/abhisheksrivastava/Library/Python/3.7/lib/python/site-packages/scipy/stats/stats.py", line 2017, in percentileofscore
    left = np.count_nonzero(a < score)
TypeError: '<' not supported between instances of 'NoneType' and 'float'

出了什么问题？我在 YouTube 视频中看到了相同的代码。我几乎没有使用 Python 的经验

编辑：

我也试过

print(type(final_df['One-Year Price Return'])) 
print(type(final_df['Six-Month Price Return'])) 
print(type(final_df['Three-Month Price Return'])) 
print(type(final_df['One-Month Price Return'])) 
for row in final_df.index:
  final_df.loc[row, 'One-Year Percentile Return'] = score(final_df['One-Year Price Return'], final_df.loc[row, 'One-Year Price Return'])
  final_df.loc[row, 'Six-Month Percentile Return'] = score(final_df['Six-Month Price Return'], final_df.loc[row, 'Six-Month Price Return'])
  final_df.loc[row, 'Three-Month Percentile Return'] = score(final_df['Three-Month Price Return'], final_df.loc[row, 'Three-Month Price Return'])
  final_df.loc[row, 'One-Month Percentile Return'] = score(final_df['One-Month Price Return'], final_df.loc[row, 'One-Month Price Return'])
print(final_df)

但它仍然得到同样的错误

<class 'pandas.core.series.Series'>
<class 'pandas.core.series.Series'>
<class 'pandas.core.series.Series'>
<class 'pandas.core.series.Series'>
<class 'pandas.core.series.Series'>
Traceback (most recent call last):
  File "program.py", line 71, in <module>
    final_df.loc[row, 'One-Year Percentile Return'] = score(final_df['One-Year Price Return'], final_df.loc[row, 'OneYear Price Return'])
  File "/Users/abhisheksrivastava/Library/Python/3.7/lib/python/site-packages/scipy/stats/stats.py", line 2017, in percentileofscore
    left = np.count_nonzero(a < score)
TypeError: '<' not supported between instances of 'NoneType' and 'float'

标签： pythonpandas

解决方案

@Taras Mogetich 写的非常正确，但是您可能需要将 if 语句放在它自己的 for 循环中。丽可这样：

for row in hqm_dataframe.index:
    for time_period in time_periods:
    
        change_col = f'{time_period} Price Return'
        percentile_col = f'{time_period} Return Percentile'
        if hqm_dataframe.loc[row, change_col] == None:
            hqm_dataframe.loc[row, change_col] = 0.0

然后分别：

for row in hqm_dataframe.index:
    for time_period in time_periods:
    
        change_col = f'{time_period} Price Return'
        percentile_col = f'{time_period} Return Percentile'

        hqm_dataframe.loc[row, percentile_col] = score(hqm_dataframe[change_col], hqm_dataframe.loc[row, change_col])

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