pandas - Cannot cast IntervalIndex to dtype int32 error when plotting an interval in python

Question

I have this code:

plt.subplot(121)
df=pd.DataFrame()
df['age']=[1,2,3,4,5,6,7,8,9,0,2,3,4,5,6,7,8,9,0,4,1,2,3,4,5,6,7,8,9,0]
df['age_cat']=pd.cut(age,bins=list(np.arange(1, 10, 2)))
df.groupby('age_cat')['age'].count().plot(kind='bar')

but when I run this code, I am getting this error:

TypeError: Cannot cast IntervalIndex to dtype int32

I am trying to plot the histogram of age values. I simplified the code to show the error.

It seems that the error is related to the plot function as if I remove it, the code works.

Edit 1

changed the code to this:

plt.subplot(121)
df=pd.DataFrame()
df['age']=[1,2,3,4,5,6,7,8,9,0,2,3,4,5,6,7,8,9,0,4,1,2,3,4,5,6,7,8,9,0]
df['age_cat']=pd.cut(df['age'],bins=list(np.arange(1, 10, 2)))
df.groupby('age_cat')['age'].count().plot(kind='bar')   

But still the same error message.

My library versions are:

absl-py                0.11.0   
astunparse             1.6.3    
async-generator        1.10     
attrs                  20.3.0   
backcall               0.2.0    
bleach                 3.2.1
cachetools             4.2.0
certifi                2020.12.5
chardet                4.0.0
colorama               0.4.4
cycler                 0.10.0
decorator              4.4.2
defusedxml             0.6.0
entrypoints            0.3
flatbuffers            1.12
gast                   0.3.3
google-auth            1.24.0
google-auth-oauthlib   0.4.2
google-pasta           0.2.0
grpcio                 1.32.0
h5py                   2.10.0
idna                   2.10
ipykernel              5.4.3
ipython                7.19.0
ipython-genutils       0.2.0
jedi                   0.18.0
Jinja2                 2.11.2
joblib                 1.0.0
jsonschema             3.2.0
jupyter-client         6.1.11
jupyter-core           4.7.0
jupyterlab-pygments    0.1.2
Keras-Preprocessing    1.1.2
kiwisolver             1.3.1
Markdown               3.3.3
MarkupSafe             1.1.1
matplotlib             3.3.3
mistune                0.8.4
nbclient               0.5.1
nbconvert              6.0.7
nbformat               5.1.2
nest-asyncio           1.4.3
numpy                  1.19.3
oauthlib               3.1.0
opt-einsum             3.3.0
packaging              20.8
pandas                 1.2.0
pandocfilters          1.4.3
parso                  0.8.1
pickleshare            0.7.5
Pillow                 8.1.0
pip                    20.3.3
prompt-toolkit         3.0.10
protobuf               3.14.0
pyasn1                 0.4.8
pyasn1-modules         0.2.8
Pygments               2.7.4
pyparsing              2.4.7
pyrsistent             0.17.3
python-dateutil        2.8.1
pytz                   2020.5
pywin32                300
pyzmq                  21.0.1
requests               2.25.1
requests-oauthlib      1.3.0
rsa                    4.7
scikit-learn           0.24.0
scipy                  1.6.0
seaborn                0.11.1
setuptools             49.2.1
six                    1.15.0
tabulate               0.8.7
tensorboard            2.4.1
tensorboard-plugin-wit 1.7.0
tensorflow             2.4.0
tensorflow-estimator   2.4.0
termcolor              1.1.0
testpath               0.4.4
tf                     1.0.0
threadpoolctl          2.1.0
tornado                6.1
traitlets              5.0.5
typing-extensions      3.7.4.3
urllib3                1.26.2
wcwidth                0.2.5
webencodings           0.5.1
Werkzeug               1.0.1
wheel                  0.36.2
wrapt                  1.12.1

question from:https://stackoverflow.com/questions/65849724/cannot-cast-intervalindex-to-dtype-int32-error-when-plotting-an-interval-in-pyth

Answer 1

Looks like you are cutting the wrong thing, should be df['age'] , not age.

df['age_cat']=pd.cut(df['age'],bins=list(np.arange(1, 10, 2)))

Output:

---

Some side notes:

1. You don't need to wrap list around np.arange.
2. You can do value_counts with bins:

df['age'].value_counts(bins=np.arange(1, 10, 2)).plot.bar()

which gives: