Python 当传递一个子集pandas.DataFrame时，numpy.historogram2d引发异常

熊猫数据帧与numpy historogram2d函数交互时出现问题。特别是当此代码正常执行时

import numpy
import pandas
df = pandas.DataFrame(np.random.randn(100, 2), columns=list('AB'))
hist, xe, ye = numpy.histogram2d(df["A"], df["B"])

在这段代码中，我创建了一个包含数据帧子集的直方图

    import numpy
    import pandas
    df = pandas.DataFrame(np.random.randn(100, 2), columns=list('AB'))
    dfSubset = pandas.DataFrame(df[df["A"] < 0])
    hist, xe, ye = numpy.histogram2d(dfSubset["A"], dfSubset["B"])

谢谢大家!

更改行：

hist, xe, ye = numpy.histogram2d(dfSubset["A"], dfSubset["B"])

致：

将序列强制为numpy数组

Babel==0.9.4
Beaker==1.3.1
Jinja2==2.2.1
Magic-file-extensions==0.1
Mako==0.3.4
MarkupSafe==0.9.2
OpenEye-python2.6-redhat-6-x64==2013.10.3
PIL==1.1.6
Pygments==1.1.1
SSSDConfig==1.9.2
Sphinx==0.6.6
argparse==1.2.1
backports.ssl-match-hostname==3.4.0.2
cas==0.15
cups==1.0
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decorator==3.0.1
docutils==0.6
ethtool==0.6
firstboot==1.110
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git-remote-helpers==0.1.0
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iotop==0.3.2
ipapython==3.0.0
ipython==1.1.0
iwlib==1.0
kerberos==1.0
lxml==2.2.3
matplotlib==1.1.1
netaddr==0.7.5
nose==0.10.4
numpy==1.8.0
pandas==0.13.0
paramiko==1.7.5
patsy==0.2.1
pyOpenSSL==0.10
pycrypto==2.0.1
pycurl==7.19.0
pygpgme==0.1
python-dateutil==2.2
python-default-encoding==0.1
python-ldap==2.3.10
python-meh==0.11
python-nss==0.11
pytz==2013.9
pyxdg==0.18
pyzmq==14.0.1
qpid-python==0.14
qpid-tools==0.14
scdate==1.9.60
scikit-learn==0.14.1
scipy==0.13.2
sckdump==2.0.5
scservices==0.99.45
scservices.dbus==0.99.45
six==1.5.2
slip==0.2.20
slip.dbus==0.2.20
slip.gtk==0.2.20
smbc==1.0
stevedore==0.13
sympy==0.7.4.1
tornado==3.2
urlgrabber==3.9.1
virtinst==0.600.0
virtualenv==1.11.1
virtualenv-clone==0.2.4
virtualenvwrapper==4.2
yum-metadata-parser==1.1.2

hist, xe, ye = numpy.histogram2d(dfSubset["A"], dfSubset["B"])

hist, xe, ye = numpy.histogram2d(dfSubset["A"].values, dfSubset["B"].values)