In PANDAS, how to get the index of a known value?

Question

If we have a known value in a column, how can we get its index-value? For example:

In [148]: a = pd.DataFrame(np.arange(10).reshape(5,2),columns=[\'c1\',\'c2\'         


        

Answer 1

There might be more than one index map to your value, it make more sense to return a list:

In [48]: a
Out[48]: 
   c1  c2
0   0   1
1   2   3
2   4   5
3   6   7
4   8   9

In [49]: a.c1[a.c1 == 8].index.tolist()
Out[49]: [4]