df.index pandas code example

Example 1: finding the index of an element in a pandas df

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]

Example 2: pandas index

How to add index to the DataFrame at runtime

df["patient"] = ["patient-" + str( i ) for i in range( max( df.index ) + 1  )]
df.set_index( "patient", inplace=True )
---------------------------------------------------------------------                 
patient = pandas.Series( ["patient-" + str( i ) for i in range( max( df.index ) + 1 )] )
df.index = patient
---------------------------------------------------------------------
df.index = ["patient-" + str( i ) for i in range( max( df.index ) + 1 )]

Example 3: pandas df by row index

indices = [133, 22, 19, 203, 14, 1]
df_by_indices = df.iloc[indices, :]

Example 4: df.index

The index (row labels) of the DataFrame.

Example 5: indexing column in pandas

In [8]: age_sex = titanic[["Age", "Sex"]]

In [9]: age_sex.head()
Out[9]: 
    Age     Sex
0  22.0    male
1  38.0  female
2  26.0  female
3  35.0  female
4  35.0    male

Example 6: indexing column in pandas

In [10]: type(titanic[["Age", "Sex"]])
Out[10]: pandas.core.frame.DataFrame