Basic Indexing with Pandas

Here's how to do indexing with Pandas.

Pretend with have this DataFrame called snakes.

          type    speed lifespan toxicity
    0     cobra     1       2       4
    1     viper     4       5       1       
    2     python    7       8       9

Indexing By Column

Using Column Names

# just one column
snakes['speed']

# multiple columns
snakes[['speed', 'lifespan']]

Using Column Numbers

snake_columns = snakes.columns

# just one column
speed_col = snake_columns[0]
snakes[speed_col]

# multiple columns
speed_and_lifespan_cols = snake_columns[0:2]
snakes[speed_and_lifespan_cols]

Indexing By Row

Using Row Numbers

# just one row
snakes.iloc[1] # this is the viper row

# multiple rows
snakes.iloc[[0,2]] # this is the viper row and the python row

Using Row Names

To index by row names, you'll need to set the index first. By default, you'll usually just have an index of integers. Instead of using .iloc, which is for indexing by row number, we're going to use .loc.

# set the index
snakes = snakes.set_index('type')

# just one row
snakes.loc['viper']

# multiple rows
snakes.loc[['viper', 'python']]