Python 3中提供的
我注意到这已经是GitHub上的一个问题了。有人有任何代码可以将Pandas DataFrame转换为Orange Table吗？
明确地说，我有下表。
user hotel star_rating user home_continent gender
0 1 39 4.0 1 2 female
1 1 44 3.0 1 2 female
2 2 63 4.5 2 3 female
3 2 2 2.0 2 3 female
4 3 26 4.0 3 1 male
5 3 37 5.0 3 1 male
6 3 63 4.5 3 1 male
Orange包的文档并没有涵盖所有细节。根据lib_kernel.cpp，Table._init__(Domain, numpy.ndarray)仅适用于int和float。
他们确实应该为pandas.DataFrames提供一个C级接口，或者至少为numpy.dtype("str")提供支持。
更新：添加了table2df，df2table通过使用numpy作为int和float，性能得到了极大的提高。
将这段脚本保存在您的橙色python脚本集合中，现在您已经在橙色环境中配备了熊猫。
用法：a_pandas_dataframe = table2df( a_orange_table )、a_orange_table = df2table( a_pandas_dataframe )
注意：此脚本仅适用于Python 2.x，请参阅@DustinTang对Python 3.x兼容脚本的回答。
import pandas as pd
import numpy as np
import Orange
#### For those who are familiar with pandas
#### Correspondence:
#### value <-> Orange.data.Value
#### NaN <-> ["?", "~", "."] # Don't know, Don't care, Other
#### dtype <-> Orange.feature.Descriptor
#### category, int <-> Orange.feature.Discrete # category: > pandas 0.15
#### int, float <-> Orange.feature.Continuous # Continuous = core.FloatVariable
#### # refer to feature/__init__.py
#### str <-> Orange.feature.String
#### object <-> Orange.feature.Python
#### DataFrame.dtypes <-> Orange.data.Domain
#### DataFrame.DataFrame <-> Orange.data.Table = Orange.orange.ExampleTable
#### # You will need this if you are reading sources
def series2descriptor(d, discrete=False):
if d.dtype is np.dtype("float"):
return Orange.feature.Continuous(str(d.name))
elif d.dtype is np.dtype("int"):
return Orange.feature.Continuous(str(d.name), number_of_decimals=0)
else:
t = d.unique()
if discrete or len(t) < len(d) / 2:
t.sort()
return Orange.feature.Discrete(str(d.name), values=list(t.astype("str")))
else:
return Orange.feature.String(str(d.name))
def df2domain(df):
featurelist = [series2descriptor(df.icol(col)) for col in xrange(len(df.columns))]
return Orange.data.Domain(featurelist)
def df2table(df):
# It seems they are using native python object/lists internally for Orange.data types (?)
# And I didn't find a constructor suitable for pandas.DataFrame since it may carry
# multiple dtypes
# --> the best approximate is Orange.data.Table.__init__(domain, numpy.ndarray),
# --> but the dtype of numpy array can only be "int" and "float"
# --> * refer to src/orange/lib_kernel.cpp 3059:
# --> * if (((*vi)->varType != TValue::INTVAR) && ((*vi)->varType != TValue::FLOATVAR))
# --> Documents never mentioned >_<
# So we use numpy constructor for those int/float columns, python list constructor for other
tdomain = df2domain(df)
ttables = [series2table(df.icol(i), tdomain[i]) for i in xrange(len(df.columns))]
return Orange.data.Table(ttables)
# For performance concerns, here are my results
# dtndarray = np.random.rand(100000, 100)
# dtlist = list(dtndarray)
# tdomain = Orange.data.Domain([Orange.feature.Continuous("var" + str(i)) for i in xrange(100)])
# tinsts = [Orange.data.Instance(tdomain, list(dtlist[i]) )for i in xrange(len(dtlist))]
# t = Orange.data.Table(tdomain, tinsts)
#
# timeit list(dtndarray) # 45.6ms
# timeit [Orange.data.Instance(tdomain, list(dtlist[i])) for i in xrange(len(dtlist))] # 3.28s
# timeit Orange.data.Table(tdomain, tinsts) # 280ms
# timeit Orange.data.Table(tdomain, dtndarray) # 380ms
#
# As illustrated above, utilizing constructor with ndarray can greatly improve performance
# So one may conceive better converter based on these results
def series2table(series, variable):
if series.dtype is np.dtype("int") or series.dtype is np.dtype("float"):
# Use numpy
# Table._init__(Domain, numpy.ndarray)
return Orange.data.Table(Orange.data.Domain(variable), series.values[:, np.newaxis])
else:
# Build instance list
# Table.__init__(Domain, list_of_instances)
tdomain = Orange.data.Domain(variable)
tinsts = [Orange.data.Instance(tdomain, [i]) for i in series]
return Orange.data.Table(tdomain, tinsts)
# 5x performance
def column2df(col):
if type(col.domain[0]) is Orange.feature.Continuous:
return (col.domain[0].name, pd.Series(col.to_numpy()[0].flatten()))
else:
tmp = pd.Series(np.array(list(col)).flatten()) # type(tmp) -> np.array( dtype=list (Orange.data.Value) )
tmp = tmp.apply(lambda x: str(x[0]))
return (col.domain[0].name, tmp)
def table2df(tab):
# Orange.data.Table().to_numpy() cannot handle strings
# So we must build the array column by column,
# When it comes to strings, python list is used
series = [column2df(tab.select(i)) for i in xrange(len(tab.domain))]
series_name = [i[0] for i in series] # To keep the order of variables unchanged
series_data = dict(series)
print series_data
return pd.DataFrame(series_data, columns=series_name)
下面是github 上一个已解决问题的答案
from Orange.data.pandas_compat import table_from_frame
out_data = table_from_frame(df)
其中df是您的dataFrame。到目前为止，我只注意到，如果数据源不是100%干净且符合所需的ISO标准，则需要手动定义一个域来处理日期。
我意识到这是一个老问题，与第一次被问到时相比有了很大的变化，但这个问题在谷歌搜索结果中名列前茅。
from Orange.data.pandas_compat import table_from_frame,table_to_frame
df= table_to_frame(in_data)
#here you go
out_data = table_from_frame(df)
基于Creo 的答案
为了将pandas DataFrame转换为Orange Table，您需要构造一个域，该域指定列类型。
对于连续变量，您只需要提供变量的名称，但对于离散变量，您还需要提供所有可能值的列表。
以下代码将为您的DataFrame构建一个域，并将其转换为橙色表：
import numpy as np
from Orange.feature import Discrete, Continuous
from Orange.data import Domain, Table
domain = Domain([
Discrete('user', values=[str(v) for v in np.unique(df.user)]),
Discrete('hotel', values=[str(v) for v in np.unique(df.hotel)]),
Continuous('star_rating'),
Discrete('user', values=[str(v) for v in np.unique(df.user)]),
Discrete('home_continent', values=[str(v) for v in np.unique(df.home_continent)]),
Discrete('gender', values=['male', 'female'])], False)
table = Table(domain, [map(str, row) for row in df.as_matrix()])
需要映射（str，row）步骤，以便Orange知道数据包含离散特征的值（而不是值列表中的值索引）。
此代码是从@TurtleIzzy为Python3修订的。
import numpy as np
from Orange.data import Table, Domain, ContinuousVariable, DiscreteVariable
def series2descriptor(d):
if d.dtype is np.dtype("float") or d.dtype is np.dtype("int"):
return ContinuousVariable(str(d.name))
else:
t = d.unique()
t.sort()
return DiscreteVariable(str(d.name), list(t.astype("str")))
def df2domain(df):
featurelist = [series2descriptor(df.iloc[:,col]) for col in range(len(df.columns))]
return Domain(featurelist)
def df2table(df):
tdomain = df2domain(df)
ttables = [series2table(df.iloc[:,i], tdomain[i]) for i in range(len(df.columns))]
ttables = np.array(ttables).reshape((len(df.columns),-1)).transpose()
return Table(tdomain , ttables)
def series2table(series, variable):
if series.dtype is np.dtype("int") or series.dtype is np.dtype("float"):
series = series.values[:, np.newaxis]
return Table(series)
else:
series = series.astype('category').cat.codes.reshape((-1,1))
return Table(series)
类似的东西？
table = Orange.data.Table(df.as_matrix())
Orange中的列将获得通用名称（a1，a2…）。如果要从数据帧复制名称和类型，请构造Orange.data.Domain对象(http://docs.orange.biolab.si/reference/rst/Orange.data.domain.html#Orange.data.Domain.init），并将其作为上面的第一个参数传递。
请参阅中的构造函数http://docs.orange.biolab.si/reference/rst/Orange.data.table.html.
table_from_frame不允许定义类列，因此，生成的表不能直接用于训练分类模型。我调整了table_from_frame函数，使其可以定义类列。请注意，类名应该作为一个附加参数给出。
"""Pandas DataFrame↔Table conversion helpers"""
import numpy as np
import pandas as pd
from pandas.api.types import (
is_categorical_dtype, is_object_dtype,
is_datetime64_any_dtype, is_numeric_dtype,
)
from Orange.data import (
Table, Domain, DiscreteVariable, StringVariable, TimeVariable,
ContinuousVariable,
)
__all__ = ['table_from_frame', 'table_to_frame']
def table_from_frame(df,class_name, *, force_nominal=False):
"""
Convert pandas.DataFrame to Orange.data.Table
Parameters
----------
df : pandas.DataFrame
force_nominal : boolean
If True, interpret ALL string columns as nominal (DiscreteVariable).
Returns
-------
Table
"""
def _is_discrete(s):
return (is_categorical_dtype(s) or
is_object_dtype(s) and (force_nominal or
s.nunique() < s.size**.666))
def _is_datetime(s):
if is_datetime64_any_dtype(s):
return True
try:
if is_object_dtype(s):
pd.to_datetime(s, infer_datetime_format=True)
return True
except Exception: # pylint: disable=broad-except
pass
return False
# If df index is not a simple RangeIndex (or similar), put it into data
if not (df.index.is_integer() and (df.index.is_monotonic_increasing or
df.index.is_monotonic_decreasing)):
df = df.reset_index()
attrs, metas,calss_vars = [], [],[]
X, M = [], []
# Iter over columns
for name, s in df.items():
name = str(name)
if name == class_name:
discrete = s.astype('category').cat
calss_vars.append(DiscreteVariable(name, discrete.categories.astype(str).tolist()))
X.append(discrete.codes.replace(-1, np.nan).values)
elif _is_discrete(s):
discrete = s.astype('category').cat
attrs.append(DiscreteVariable(name, discrete.categories.astype(str).tolist()))
X.append(discrete.codes.replace(-1, np.nan).values)
elif _is_datetime(s):
tvar = TimeVariable(name)
attrs.append(tvar)
s = pd.to_datetime(s, infer_datetime_format=True)
X.append(s.astype('str').replace('NaT', np.nan).map(tvar.parse).values)
elif is_numeric_dtype(s):
attrs.append(ContinuousVariable(name))
X.append(s.values)
else:
metas.append(StringVariable(name))
M.append(s.values.astype(object))
return Table.from_numpy(Domain(attrs, calss_vars, metas),
np.column_stack(X) if X else np.empty((df.shape[0], 0)),
None,
np.column_stack(M) if M else None)
这在中运行良好
from Orange.data.pandas_compat import table_from_frame,table_to_frame
import pandas as pd
# read the input data into pandas data-frame
df= table_to_frame(in_data)
# perform all data operations / wrangling
# for example only few columns are required in output
df = df[['Col1', 'Col2']]
# Final output
out_data = table_from_frame(df)