Researchpy：summary_cont() 页面示例中的警告

Question

researchpy 的 summary_cont() page 有一个例子，给出的是；

import numpy, pandas, researchpy

numpy.random.seed(12345678)

df = pandas.DataFrame(numpy.random.randint(10, size= (100, 2)),
                  columns= ['healthy', 'non-healthy'])
df['tx'] = ""
df['tx'].iloc[0:50] = "Placebo"
df['tx'].iloc[50:101] = "Experimental"

df['dose'] = ""
df['dose'].iloc[0:26] = "10 mg"
df['dose'].iloc[26:51] = "25 mg"
df['dose'].iloc[51:76] = "10 mg"
df['dose'].iloc[76:101] = "25 mg"

产生警告

summury_cont.py:8: SettingWithCopyWarning: 
A value is trying to be set on a copy of a slice from a DataFrame

See the caveats in the documentation: https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#returning-a-view-versus-a-copy
  df['tx'].iloc[0:50] = "Placebo"

这个要求看这个page

转换成这个

df.loc[:, ('tx')].iloc[0:50] = "Placebo"

它仍然产生相同的警告。正确的做法是什么？

Answer 1

值分配如下所示。左边是行索引，右边是列名。使用显式 'loc' 索引。可以看出显式和隐式'iloc'索引的区别

import numpy, pandas

numpy.random.seed(12345678)

df = pandas.DataFrame(data = numpy.random.randint(10, size= (100, 2)),
                  columns= ['healthy', 'non-healthy'])

df['tx'] = ""
df.loc[0:50, 'tx'] = "Placebo"
df.loc[50:101, 'tx'] = "Experimental"

df['dose'] = ""
df.loc[0:26, 'dose'] = "10 mg"
df.loc[26:51, 'dose'] = "25 mg"
df.loc[51:76, 'dose'] = "10 mg"
df.loc[76:101, 'dose'] = "25 mg"
print(df)

输出

    healthy  non-healthy            tx   dose
0         3            2       Placebo  10 mg
1         4            1       Placebo  10 mg
2         0            1       Placebo  10 mg
3         8            2       Placebo  10 mg
4         6            6       Placebo  10 mg
..      ...          ...           ...    ...
95        8            5  Experimental  25 mg
96        8            3  Experimental  25 mg
97        4            0  Experimental  25 mg
98        4            3  Experimental  25 mg
99        6            9  Experimental  25 mg

Researchpy：summary_cont() 页面示例中的警告

Researchpy : Warning in the example of summary_cont() page

python

dataframe

pandas