index row pandas code example

Example 1: loc and iloc in pandas

iloc - default indexes (system generated)
loc - table indexes or we manually given indexes

Example 2: pandas df by row index

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

Example 3: loc and iloc in pandas

iloc slicing gives all the data upto the position that is passed as argument
loc gives all the data upto the label that is passed as argument
n = pd.Series([1,2,3,4],index = [0,1,2,3])
print("With iloc we got")
print(n.iloc[:2])
print("With loc we got")
print(n.loc[:2])

<Output>
With iloc we got
0    1
1    2
dtype: int64
With loc we got
0    1
1    2
2    3
dtype: int64

Example 4: add an index column in range dataframe

df = df.loc[df.index.repeat(df['a'])]   
df['c'] = df.groupby(level=0).cumcount() + 1
df = df.reset_index(drop=True)
print (df)
   a  b  c
0  1  x  1
1  2  y  1
2  2  y  2
3  3  z  1
4  3  z  2
5  3  z  3

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