異なるIPythonバージョンのmatplotlibを使用してパンダデータフレームからプロットするときにエラーが発生する

Question

偽のデータからダミーのヒストグラムを単純にプロットしようとすると、奇妙な問題に直面しています（pandasドキュメントのコピー/ペースト）。 このクラッシュの原因は何ですか？

#!/usr/bin/python3 
# -*- coding: utf-8 -*- 


import pandas as pd 
import numpy as np 

import matplotlib.pyplot as plt 

df = pd.DataFrame({'A' : [1,2,3,4], 
        'C' : pd.Series(1,index=list(range(4)),dtype='float32'), 
        'D' : np.array([3] * 4,dtype='int32'), 
        'E' : pd.Categorical(["test","train","test","train"]), 
        'F' : 'foo' }) 
c=['A'] 

plt.figure() 
plt.hist(df[c]) 
plt.show() 

ipython2 ttplot.py -iで実行する場合、私は、次の出力得る：ipython3 ttplot.py -iと

Python 2.7.12 |Anaconda 4.1.1 (64-bit)| (default, Jul 2 2016, 17:42:40) 
Type "copyright", "credits" or "license" for more information. 

IPython 4.2.0 -- An enhanced Interactive Python. 
?   -> Introduction and overview of IPython's features. 
%quickref -> Quick reference. 
help  -> Python's own help system. 
object? -> Details about 'object', use 'object??' for extra details. 
--------------------------------------------------------------------------- 
TypeError         Traceback (most recent call last) 
/srv/logs/tiaki/sentryo/exps/tools/ttplot.py in <module>() 
    28 
    29 plt.figure() 
---> 30 plt.hist(df[c]) 
    31 plt.show() 
    32 

/home/inendi/anaconda2/lib/python2.7/site-packages/matplotlib/pyplot.pyc in hist(x, bins, range, normed, weights, cumulative, bottom, histtype, align, orientation, rwidth, log, color, label, stacked, hold, data, **kwargs) 
    2956      histtype=histtype, align=align, orientation=orientation, 
    2957      rwidth=rwidth, log=log, color=color, label=label, 
-> 2958      stacked=stacked, data=data, **kwargs) 
    2959  finally: 
    2960   ax.hold(washold) 

/home/inendi/anaconda2/lib/python2.7/site-packages/matplotlib/__init__.pyc in inner(ax, *args, **kwargs) 
    1810      warnings.warn(msg % (label_namer, func.__name__), 
    1811         RuntimeWarning, stacklevel=2) 
-> 1812    return func(ax, *args, **kwargs) 
    1813   pre_doc = inner.__doc__ 
    1814   if pre_doc is None: 

/home/inendi/anaconda2/lib/python2.7/site-packages/matplotlib/axes/_axes.pyc in hist(self, x, bins, range, normed, weights, cumulative, bottom, histtype, align, orientation, rwidth, log, color, label, stacked, **kwargs) 
    5993    xmax = -np.inf 
    5994    for xi in x: 
-> 5995     if len(xi) > 0: 
    5996      xmin = min(xmin, xi.min()) 
    5997      xmax = max(xmax, xi.max()) 

TypeError: len() of unsized object 

In [1]: 

、私は次の出力得る：異なるバージョンにどういうわけ

Python 3.4.2 (default, Oct 8 2014, 10:45:20) 
Type "copyright", "credits" or "license" for more information. 

IPython 5.1.0 -- An enhanced Interactive Python. 
?   -> Introduction and overview of IPython's features. 
%quickref -> Quick reference. 
help  -> Python's own help system. 
object? -> Details about 'object', use 'object??' for extra details. 
--------------------------------------------------------------------------- 
KeyError         Traceback (most recent call last) 
/usr/local/lib/python3.4/dist-packages/pandas/indexes/base.py in get_loc(self, key, method, tolerance) 
    2133    try: 
-> 2134     return self._engine.get_loc(key) 
    2135    except KeyError: 

pandas/index.pyx in pandas.index.IndexEngine.get_loc (pandas/index.c:4164)() 

pandas/index.pyx in pandas.index.IndexEngine.get_loc (pandas/index.c:4028)() 

pandas/src/hashtable_class_helper.pxi in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:13166)() 

pandas/src/hashtable_class_helper.pxi in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:13120)() 

KeyError: 0 

During handling of the above exception, another exception occurred: 

KeyError         Traceback (most recent call last) 
/srv/logs/tiaki/sentryo/exps/tools/ttplot.py in <module>() 
    28 
    29 plt.figure() 
---> 30 plt.hist(df[c]) 
    31 plt.show() 
    32 

/usr/lib/python3/dist-packages/matplotlib/pyplot.py in hist(x, bins, range, normed, weights, cumulative, bottom, histtype, align, orientation, rwidth, log, color, label, stacked, hold, **kwargs) 
    2894      histtype=histtype, align=align, orientation=orientation, 
    2895      rwidth=rwidth, log=log, color=color, label=label, 
-> 2896      stacked=stacked, **kwargs) 
    2897   draw_if_interactive() 
    2898  finally: 

/usr/lib/python3/dist-packages/matplotlib/axes/_axes.py in hist(self, x, bins, range, normed, weights, cumulative, bottom, histtype, align, orientation, rwidth, log, color, label, stacked, **kwargs) 
    5576   # Massage 'x' for processing. 
    5577   # NOTE: Be sure any changes here is also done below to 'weights' 
-> 5578   if isinstance(x, np.ndarray) or not iterable(x[0]): 
    5579    # TODO: support masked arrays; 
    5580    x = np.asarray(x) 

/usr/local/lib/python3.4/dist-packages/pandas/core/frame.py in __getitem__(self, key) 
    2057    return self._getitem_multilevel(key) 
    2058   else: 
-> 2059    return self._getitem_column(key) 
    2060 
    2061  def _getitem_column(self, key): 

/usr/local/lib/python3.4/dist-packages/pandas/core/frame.py in _getitem_column(self, key) 
    2064   # get column 
    2065   if self.columns.is_unique: 
-> 2066    return self._get_item_cache(key) 
    2067 
    2068   # duplicate columns & possible reduce dimensionality 

/usr/local/lib/python3.4/dist-packages/pandas/core/generic.py in _get_item_cache(self, item) 
    1384   res = cache.get(item) 
    1385   if res is None: 
-> 1386    values = self._data.get(item) 
    1387    res = self._box_item_values(item, values) 
    1388    cache[item] = res 

/usr/local/lib/python3.4/dist-packages/pandas/core/internals.py in get(self, item, fastpath) 
    3539 
    3540    if not isnull(item): 
-> 3541     loc = self.items.get_loc(item) 
    3542    else: 
    3543     indexer = np.arange(len(self.items))[isnull(self.items)] 

/usr/local/lib/python3.4/dist-packages/pandas/indexes/base.py in get_loc(self, key, method, tolerance) 
    2134     return self._engine.get_loc(key) 
    2135    except KeyError: 
-> 2136     return self._engine.get_loc(self._maybe_cast_indexer(key)) 
    2137 
    2138   indexer = self.get_indexer([key], method=method, tolerance=tolerance) 

pandas/index.pyx in pandas.index.IndexEngine.get_loc (pandas/index.c:4164)() 

pandas/index.pyx in pandas.index.IndexEngine.get_loc (pandas/index.c:4028)() 

pandas/src/hashtable_class_helper.pxi in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:13166)() 

pandas/src/hashtable_class_helper.pxi in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:13120)() 

KeyError: 0 

In [1]: 

、python2と3点matplotlibとpandasの一覧

Python2：matplot LIB： '1.5.1'、パンダ： '0.18.1'

のpython3：matplotlibの： '1.4.2'、パンダ：あなたが[[0] C] dfを使用する必要があります '0.19.1'

Answer 1

なぜなら、cは配列ではなく文字列であるからです。