3.5. Series Getitem¶

3.5.1. Range Index¶

import pandas as pd


s = pd.Series([1.1, 2.2, 3.3, None, 5.5])

s
# 0    1.1
# 1    2.2
# 2    3.3
# 3    NaN
# 4    5.5
# dtype: float64

s.index
# RangeIndex(start=0, stop=5, step=1)

s[0]        # 1.1
s[3]        # nan
s[100]      # KeyError: 100

s[-1]       # KeyError: -1
s[-100]     # KeyError: -100

3.5.2. Float and Int Index¶

import pandas as pd


s = pd.Series(
    data = [1.1, 2.2, 3.3, None, 5.5],
    index = [1, 0, 3.3, 99, -1])

s
#  1.0     1.1
#  0.0     2.2
#  3.3     3.3
#  99.0    NaN
# -1.0     5.5
# dtype: float64

s.index
# Float64Index([1.0, 0.0, 3.3, 99.0, -1.0], dtype='float64')

s[0]        # 2.2
s[3]        # KeyError: 3
s[100]      # KeyError: 100

s[-1]       # 5.5
s[-100]     # KeyError: -100

3.5.3. String Index¶

import pandas as pd


s = pd.Series(
    data = [1.1, 2.2, 3.3, None, 5.5],
    index = ['a', 'b', 'c', 'd', 'e'])

s
# a    1.1
# b    2.2
# c    3.3
# d    NaN
# e    5.5
# dtype: float64

s.index
# Index(['a', 'b', 'c', 'd', 'e'], dtype='object')

s['a']      # 1.1
s['d']      # nan
s['e']      # 5.5
s['x']      # KeyError: 'x'

s[0]        # 1.1
s[3]        # nan
s[100]      # IndexError: index 100 is out of bounds for axis 0 with size 5
s[-1]       # 5.5
s[-100]     # IndexError: index -100 is out of bounds for axis 0 with size 5

3.5.4. Date Index¶

import pandas as pd


s = pd.Series(
    data = [1.1, 2.2, 3.3, None, 5.5],
    index = pd.date_range('1999-12-30', periods=5))

s
# 1999-12-30    1.1
# 1999-12-31    2.2
# 2000-01-01    3.3
# 2000-01-02    NaN
# 2000-01-03    5.5
# Freq: D, dtype: float64

s.index
# DatetimeIndex(['1999-12-30', '1999-12-31', '2000-01-01', '2000-01-02', '2000-01-03'],
#               dtype='datetime64[ns]', freq='D')

s['2000-01-03']
# 5.5

s['2000-01']
# 2000-01-01    3.3
# 2000-01-02    NaN
# 2000-01-03    5.5
# Freq: D, dtype: float64

s['1999']
# 1999-12-30    1.1
# 1999-12-31    2.2
# Freq: D, dtype: float64

s[0]        # 1.1
s[3]        # nan
s[100]      # IndexError: index 100 is out of bounds for axis 0 with size 5
s[-1]       # 5.5
s[-100]     # IndexError: index -100 is out of bounds for axis 0 with size 5

s['a']      # KeyError: 'a'

3.5.5. Assignments¶

3.5.5.1. Series Getitem¶

Assignment: Series Getitem
Last update: 2020-10-01
Complexity level: easy
Lines of code to write: 5 lines
Estimated time of completion: 8 min
Filename: solution/series_getitem.py

English:

Set random seed to zero
Create pd.Series with 100 random numbers from standard normal distribution
Series Index are following dates since 2000
Print values:
- at 2000-02-29,
- first value in the series (without using .head()),
- last value in the series (without using .tail()),
- middle value in the series.

Polish:

Ustaw ziarno losowości na zero
Stwórz pd.Series z 100 losowymi liczbami z rozkładu normalnego
Indeksem w serii mają być kolejne dni od 2000 roku
Wypisz wartości:
- dnia 2000-02-29,
- pierwszą wartość w serii (nie używając .head()),
- ostatnią wartość w serii (nie używając .tail()),
- środkowa wartość serii.

Hints:

np.random.seed(0)
np.random.randn(10)