Description
Code Sample, a copy-pastable example if possible
In [2]: import pandas as pd
In [3]: pd.__version__
Out[3]: '0.23.0rc2'
In [4]: x = pd.DataFrame({'b': [1,2,3]}, index=[1,1,2])
In [5]: x
Out[5]:
b
1 1
1 2
2 3
In [6]: x.first_valid_index()
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-6-baa2c482d9a6> in <module>()
----> 1 x.first_valid_index()
lib/python3.5/site-packages/pandas/core/generic.py in first_valid_index(self)
8881 'klass': 'NDFrame'})
8882 def first_valid_index(self):
-> 8883 return self._find_valid_index('first')
8884
8885 @Appender(_shared_docs['valid_index'] % {'position': 'last',
lib/python3.5/site-packages/pandas/core/generic.py in _find_valid_index(self, how)
8867 # First valid value case
8868 i = is_valid.idxmax()
-> 8869 if not is_valid[i]:
8870 return None
8871 return i
lib/python3.5/site-packages/pandas/core/generic.py in __nonzero__(self)
1572 raise ValueError("The truth value of a {0} is ambiguous. "
1573 "Use a.empty, a.bool(), a.item(), a.any() or a.all()."
-> 1574 .format(self.__class__.__name__))
1575
1576 __bool__ = __nonzero__
ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().Problem description
first_valid_index did not raise on a row index with duplicate values on pandas <= 0.22.0
Expected Output
0
Output of pd.show_versions()
INSTALLED VERSIONS
commit: None
python: 3.5.4.final.0
python-bits: 64
OS: Linux
OS-release: 4.1.35-pv-ts2
machine: x86_64
processor:
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: en_US.UTF-8
pandas: 0.23.0
pytest: 3.2.1
pip: 9.0.1
setuptools: 36.4.0
Cython: None
numpy: 1.12.1
scipy: 0.19.1
pyarrow: 0.8.0
xarray: None
IPython: 6.1.0
sphinx: 1.7.5
patsy: 0.4.1
dateutil: 2.6.1
pytz: 2017.2
blosc: None
bottleneck: None
tables: 3.4.2
numexpr: 2.6.2
feather: None
matplotlib: 2.0.2
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: 4.6.0
html5lib: 0.9999999
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: 2.9.6
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None
cc @jreback