python - 将 Pandas Dataframe 列转换为 R 因子

Question

我正在尝试将 pandas 数据框的一列转换为因数，因为我试图在 R 中调用的函数需要因数。

pandas2ri.activate()    
#second column of labels has to be converted to factors
labels = read_csv(path_to_csv)
as_factor = ro.r['as.factor']
output = package.function(another_df, as_factor(labels['column_name']))

以下是我得到的错误:

rpy2.rinterface.RRuntimeError: Error in sort.list(y) : 'x' must be atomic for 'sort.list'
Have you called 'sort' on a list?

我该怎么办？

下面的可重现示例:

import pandas as pd

df = pd.DataFrame({'Col': [10, 20],
                   'x': ['Control', 'Low_Cav02']})

from rpy2 import robjects as ro

from rpy2.robjects import pandas2ri
pandas2ri.activate()

as_factor = ro.r['as.factor']

labels = as_factor(df['Col'])
print labels

labels = as_factor(df['x'])
print labels

输出:

[1] 10 20
Levels: 10 20

/Users/swetabh/Envs/damet/lib/python2.7/site-packages/rpy2/robjects/functions.py:106: UserWarning: Error in sort.list(y) : 'x' must be atomic for 'sort.list'
Have you called 'sort' on a list?

  res = super(Function, self).__call__(*new_args, **new_kwargs)
Traceback (most recent call last):
  File "damet/analysis.py", line 26, in <module>
    labels = as_factor(df['x'])
  File "/Users/swetabh/Envs/damet/lib/python2.7/site-packages/rpy2/robjects/functions.py", line 178, in __call__
    return super(SignatureTranslatedFunction, self).__call__(*args, **kwargs)
  File "/Users/swetabh/Envs/damet/lib/python2.7/site-packages/rpy2/robjects/functions.py", line 106, in __call__
    res = super(Function, self).__call__(*new_args, **new_kwargs)
rpy2.rinterface.RRuntimeError: Error in sort.list(y) : 'x' must be atomic for 'sort.list'
Have you called 'sort' on a list?

Answer 1

这对我来说工作得很好。您使用的是哪个版本的 rpy2？

编辑:下面的原始答案 - 我误解了问题

如果尝试创建 R DataFrame，rpy2 中的默认转换器会将 Python 列表转换为 R 列表。如果您想要一个 R 向量，请使用向量的构造函数。

以您的示例为例:

df = ro.DataFrame({'Col': ro.vectors.IntVector([10, 20]),
                   'x': ro.vectors.StrVector(['Control', 'Low_Cav02'])})