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[英]No axis named 1 for object type <class 'pandas.core.frame.DataFrame'>
[英]AssertionError: DataFrame Expected type <class 'pandas.core.frame.DataFrame'>, found <class 'NoneType'> instead
如何更改一個類以強制它返回一個 pandas 數據幀,而不是作為一個對象,而是以類似於函數的方式返回。
換句話說,打開這個給我錯誤AssertionError: DataFrame Expected type <class 'pandas.core.frame.DataFrame'>, found <class 'NoneType'> instead
:
最小示例:旨在返回數據幀的類
import pandas as pd
from pandas.testing import assert_frame_equal
class SumAllClassTwo:
''' class sums class_2 to class_2.5 columns then writes it to class_2'''
def __init__(self, df:pd.DataFrame):
self.df = df
def sum_all_class_two(self):
self.df['class_2'] = self.df['class_2'] + self.df['class_2.5'] # sum 2 and 2.5
self.df = self.df.drop(columns=['class_2.5']) # return new 2
return self.df
class TestSumAllClassTwo:
def test_one():
input_df = pd.DataFrame({'class_2':[1], 'class_2.5':[1]})
result = SumAllClassTwo(input_df) # don't want df as an attribute
expected = pd.DataFrame({'class_2':[2]})
assert_frame_equal(result, expected)
# run test class
TestSumAllClassTwo.test_one()
以便它返回一個數據框,作為按預期工作的類似方法,將:
等效工作方法
def sum_all_class_two_2(df:pd.DataFrame=None):
df['class_2'] = df['class_2'] + df['class_2.5'] # sum 2 and 2.5
df = df.drop(columns=['class_2.5']) # return new 2
return df
def test_sum_all_class_two_2():
expected = pd.DataFrame({'class_2':[2]})
input_df = pd.DataFrame({'class_2':[1], 'class_2.5':[1]})
result = sum_all_class_two_2(input_df)
assert_frame_equal(expected, result)
通過將class_2
和class_2.5
的第 1 行中的值相加,返回第 2 類中的 2。
主要不是答案,而是有更多空間的評論-
這是構造函數並且不返回 DF 它返回一個類引用:
result = SumAllClassTwo(input_df)
這似乎有效:
result = SumAllClassTwo(input_df).sum_all_class_two()
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