python - return default if pandas dataframe.loc location doesn't exist

Question

I find myself often having to check whether a column or row exists in a dataframe before trying to reference it. For example I end up adding a lot of code like:

if 'mycol' in df.columns and 'myindex' in df.index: x = df.loc[myindex, mycol]
else: x = mydefault

Is there any way to do this more nicely? For example on an arbitrary object I can do x = getattr(anobject, 'id', default) - is there anything similar to this in pandas? Really any way to achieve what I'm doing more gracefully?

question from:https://stackoverflow.com/questions/23403352/return-default-if-pandas-dataframe-loc-location-doesnt-exist

Answer 1

There is a method for Series:

So you could do:

df.mycol.get(myIndex, NaN)

Example:

In [117]:

df = pd.DataFrame({'mycol':arange(5), 'dummy':arange(5)})
df
Out[117]:
   dummy  mycol
0      0      0
1      1      1
2      2      2
3      3      3
4      4      4

[5 rows x 2 columns]
In [118]:

print(df.mycol.get(2, NaN))
print(df.mycol.get(5, NaN))
2
nan