Pandas DataFrame Basics

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Skill - Pandas DataFrame Basics

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Skills Required

Please make sure to have all the skills mentioned above to understand and execute the code mentioned below. Go through the above skills if necessary for reference or revision

Pandas is a python library.
DataFrame is a data structure provided by the pandas library
The image shown below tries to describe the anatomy of a DataFrame

Pandas DataFrame anatomy

Pandas DataFrame illustration

  • As shown above, a DataFrame is just like an excel sheet
  • A DataFrame has columns, where each column has a name and position
  • A DataFrame has rows, where each row also has a name and position
  • The data in of a DataFrame lies in the cells of the DataFrame. Each cell has a specific row and column
  • All the column labels of a DataFrame are called columns
  • All the row labels of a DataFrame are called index

Using Pandas DataFrame

  • Open command prompt, type the command pip install pandas and press enter. This should install pandas library in your computer.
    pip install pandas in cmd
  • In your python file write import pandas as pd at the top. Now you can the variable pd to access pandas DataFrame

Creating a DataFrame with a dictionary of lists

import pandas as pd
x = {
	"Name": ["Harris","Mr. William Henry","Miss. Elizabeth"],
	"Age": [22, 35, 58],
	"Sex": ["male", "male", "female"]
	}
df = pd.DataFrame(x)
 
print(df)
# this will print
'''
   Age               Name     Sex
0   22             Harris    male
1   35  Mr. William Henry    male
2   58    Miss. Elizabeth  female
'''

As shown above, each key of the dictionary will become a column in the DataFrame

Creating a DataFrame with a list of dictionaries

import pandas as pd
x = [
        {"Name": "Harris", "Age": 22, "Sex": "male"},
        {"Name": "Mr. William Henry", "Age": 35, "Sex": "male"},
        {"Name": "Miss. Elizabeth", "Age": 58, "Sex": "female"},
    ]
df = pd.DataFrame(x)
 
print(df)
# this will print
'''
   Age               Name     Sex
0   22             Harris    male
1   35  Mr. William Henry    male
2   58    Miss. Elizabeth  female
'''

Creating a DataFrame with a list of lists

import pandas as pd
x = [
        ["Harris", 22,"male"],
        ["Mr. William Henry", 35, "male"],
        ["Miss. Elizabeth", 58, "female"],
    ]
df = pd.DataFrame(x, columns=["Name", "Age", "Sex"])
 
print(df)
# this will print
'''
                Name  Age     Sex
0             Harris   22    male
1  Mr. William Henry   35    male
2    Miss. Elizabeth   58  female
'''

Creating a DataFrame from csv using ‘read_csv’

read the complete documentation of read_csv here
The csv used for this example can be found here

import pandas as pd

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

print(df)
# this will print
'''
                Name  Age     Sex
0             Harris   22    male
1  Mr. William Henry   35    male
2    Miss. Elizabeth   58  female
'''

This code can be run in Visual Studio Code as shown below. Make sure csv in the same folder as python file.
read_csv_demo_vs_code

Creating a DataFrame from excel using ‘read_excel’

read the complete documentation of read_excel here
The excel file used for this example can be found here

import pandas as pd

df = pd.read_excel('df_beginner.xlsx')

print(df)
# this will print
'''
                Name  Age     Sex
0             Harris   22    male
1  Mr. William Henry   35    male
2    Miss. Elizabeth   58  female
'''

This code can be run in Visual Studio Code as shown below. Make sure the xlsx file in the same folder as python file.
read_csv_demo_vs_code

Video

You can the video on this post here

Online Interpreter

Although we recommend to practice the above examples in Visual Studio Code, you can run these examples online at https://www.tutorialspoint.com/execute_python_online.php

References

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