Co je pandas?

Úvod do datové vědy v Pythonu

Hillary Green-Lerman

Lead Data Scientist, Looker

K čemu slouží pandas?

Načítání tabulkových dat z různých zdrojů
Vyhledávání konkrétních řádků nebo sloupců
Výpočet agregovaných statistik
Kombinování dat z více zdrojů

Tabulková data v pandas

Tabulková data

+-------------------------------------------------+
|        suspect        |     location    | price |
+-----------------------+-----------------+-------+
| Fred Frequentist      | Petroleum Plaza | 24.95 |
| Ronald Aylmer Fisher  | Clothing Club   | 20.15 |
+-------------------------------------------------+

DataFrame

                suspect        location  price
0      Fred Frequentist  Perolium Plaza  24.95
1  Ronald Aylmer Fisher   Clothing Club  20.15

Soubory CSV

Načtení souboru CSV

import pandas as pd

df = pd.read_csv('ransom.csv')

Zobrazení DataFrame

df = pd.read_csv('filename.csv')

print(df)

                 suspect         location          item  price
0         Kirstine Smith  Petroleum Plaza           gas  24.95
1       Fred Frequentist      Burger Mart         fries   1.95
2           Gertrude Cox      Burger Mart         fries   1.95
3   Ronald Aylmer Fisher    Clothing Club         shirt  14.25
4         Kirstine Smith    Clothing Club         dress  20.15
5       Fred Frequentist   Groceries R Us     cucumbers   2.05
6         Kirstine Smith    Clothing Club         dress  20.15
7           Gertrude Cox  Petroleum Plaza   fizzy drink   1.90
8           Gertrude Cox      Burger Mart         fries   1.95
9   Ronald Aylmer Fisher    Clothing Club         shirt  14.25
10  Ronald Aylmer Fisher  Petroleum Plaza       carwash  13.25
11  Ronald Aylmer Fisher    Clothing Club         shirt  14.25
12        Kirstine Smith  Petroleum Plaza           gas  24.95
13      Fred Frequentist   Groceries R Us          eggs   6.50
14          Gertrude Cox  Petroleum Plaza           gas  24.95
15      Fred Frequentist   Groceries R Us          eggs   6.50
16  Ronald Aylmer Fisher   Groceries R Us          eggs   6.50
17      Fred Frequentist   Groceries R Us        cheese   5.00

Prozkoumání DataFrame

df.head()

print(df.head())

                 suspect         location          item  price
0         Kirstine Smith  Petroleum Plaza           gas  24.95
1       Fred Frequentist      Burger Mart         fries   1.95
2           Gertrude Cox      Burger Mart         fries   1.95
3   Ronald Aylmer Fisher    Clothing Club         shirt  14.25
4         Kirstine Smith    Clothing Club         dress  20.15

Prozkoumání DataFrame

df.info()

print(df.info())

<class 'pandas.core.frame.DataFrame'>
RangeIndex: 26 entries, 0 to 25
Data columns (total 3 columns):
 #   Column        Non-Null Count  Dtype  
 --  ------        --------------  -----  
 0   letter_index  26 non-null     int64 
 1   letter        26 non-null     object 
 2   frequency     26 non-null     float64 
dtypes: float64(1), int64(1), object(1)
memory usage: 704.0+ bytes

Prozkoumání DataFrame

Lass uns üben!

Úvod do datové vědy v Pythonu