Learn Python – How to create a DataFrames in Python- Basic and advance

A Data Frame is a two-dimension collection of data. It is a information structure where records is saved in tabular form. Datasets are organized in rows and columns; we can shop multiple datasets in the information frame. We can function a variety of arithmetic operations, such as including column/row determination and columns/rows in the facts frame.

We can import the DataFrames from the external storage; these storages can be referred to as the SQL Database, CSV file, and an Excel file. We can also use the lists, dictionary, and from a listing of dictionary, etc.

In this tutorial, we will analyze to create the data frame in more than one ways. Let’s recognize these unique ways.

First, we want to deploy the pandas library into the Python environment.

An empty dataframe

We can create a basic empty Dataframe. The dataframe constructor wants to be called to create the DataFrame. Let’s understand the following example.

Example –

# import pandas as pd  
import pandas as pd  
  
# Calling DataFrame constructor  
df = pd.DataFrame()  
  
print(df)  

Output:

Empty DataFrame
Columns: []
Index: []

Method – 2: Create a dataframe using List

We can create dataframe the usage of a single listing or list of lists. Let’s apprehend the following example.

Example –

# importing pandas library  
import pandas as pd  
  
# string values in the list   
lst = ['Java', 'Python', 'C', 'C++',  
         'JavaScript', 'Swift', 'Go']  
  
# Calling DataFrame constructor on list  
dframe = pd.DataFrame(lst)  
print(dframe)  

Output:

0        Java
1      Python
2           C
3         C++
4   JavaScript
5       Swift
6          Go

Method – 3: Create Dataframe from dict of ndarray/lists

The dict of ndarray/lists can be used to create a dataframe, all the ndarray should be of the identical length. The index will be a range(n) by means of default; the place n denotes the array length. Let’s recognize the following example.

Example –

import pandas as pd  
  
# assign data of lists.  
data = {'Name': ['Tom', 'Joseph', 'Krish', 'John'], 'Age': [20, 21, 19, 18]}  
  
# Create DataFrame  
df = pd.DataFrame(data)  
  
# Print the output.  
print(df)  

Output:

     Name  Age
0     Tom   20
1  Joseph   21
2   Krish   19
3    John   18

Method – 4: Create a indexes Dataframe using arrays

Let’s understand the following instance to create the indexes dataframe using arrays.

Example –

# DataFrame using arrays.  
import pandas as pd  
  
# assign data of lists.  
data = {'Name':['Renault', 'Duster', 'Maruti', 'Honda City'], 'Ratings':[9.0, 8.0, 5.0, 3.0]}  
  
# Creates pandas DataFrame.  
df = pd.DataFrame(data, index =['position1', 'position2', 'position3', 'position4'])  
  
# print the data  
print(df)  

Output:

               Name      Ratings
position1     Renault      9.0
position2      Duster      8.0
position3      Maruti      5.0
position4    Honda City      3.0

Explanation –

In the above code, we have described the column title with the a variety of automobile names and their ratings. We used the array to create indexes.

Method – 5: Create Dataframe from list of dicts

We can omit the lists of dictionaries as input information to create the Pandas dataframe. The column names are taken as keys via default. Let’s understand the following example.

Example –

# the example is to create  
# Pandas DataFrame by lists of dicts.  
import pandas as pd  
  
# assign values to lists.  
data = [{'A': 10, 'B': 20, 'C':30}, {'x':100, 'y': 200, 'z': 300}]  
  
# Creates DataFrame.  
df = pd.DataFrame(data)  
  
# Print the data  
print(df)  

Output:

    A      B      C      x      y      z
0  10.0  20.0  30.0    NaN    NaN    NaN
1   NaN   NaN   NaN  100.0  200.0  300.0

Let’s understand some other example to create the pandas dataframe from listing of dictionaries with both row index as nicely as column index.

Example – 2:

import pandas as pd  
  
# assigns values to lists.  
data = [{'x': 1, 'y': 2}, {'A': 15, 'B': 17, 'C': 19}]  
  
# With two column indices, values same  
# as dictionary keys  
dframe1 = pd.DataFrame(data, index =['first', 'second'], columns =['x', 'y'])  
  
# With two column indices with  
# one index with other name  
dframe2 = pd.DataFrame(data, index =['first', 'second'], columns =['x', 'y1'])  
  
# print the first data frame  
print (dframe1, "\n")  
# Print the second DataFrame.  
print (dframe2)  

Output:

             x    y
first   1.0   2.0
second  NaN NaN 

             x    y1
first   1.0 NaN
second NaN NaN

Let’s apprehend some other example to create dataframe through passing lists of dictionary and rows.

Example – 3

# The example is to create  
# Pandas DataFrame by passing lists of  
# Dictionaries and row indices.  
import pandas as pd  
  
# assign values to lists  
data = [{'x': 2, 'z':3}, {'x': 10, 'y': 20, 'z': 30}]  
  
# Creates padas DataFrame by passing  
# Lists of dictionaries and row index.  
dframe = pd.DataFrame(data, index =['first', 'second'])  
  
# Print the dataframe  
print(dframe)  

Output:

         x     y   z
first    2   NaN   3
second  10  20.0  30

We have discussed the three approaches to create the dataframe the use of the lists of dictionary.

Method – 6: Create Dataframe the usage of the zip() function

The zip() feature is used to merge the two lists. Let’s apprehend the following example.

Example –

# The example is to create  
# pandas dataframe from lists using zip.  
  
import pandas as pd  
  
# List1  
Name = ['tom', 'krish', 'arun', 'juli']  
  
# List2  
Marks = [95, 63, 54, 47]  
  
#  two lists.  
# and merge them by using zip().  
list_tuples = list(zip(Name, Marks))  
  
# Assign data to tuples.  
print(list_tuples)  
  
# Converting lists of tuples into  
# pandas Dataframe.  
dframe = pd.DataFrame(list_tuples, columns=['Name', 'Marks'])  
  
# Print data.  
print(dframe)  

Output:

[('john', 95), ('krish', 63), ('arun', 54), ('juli', 47)]
    Name  Marks
0   john     95
1  krish     63
2   arun     54
3   juli     47

Method – 7: Create Dataframe from Dicts of series

The dictionary can be exceeded to create a dataframe. We can use the Dicts of series where the subsequent index is the union of all the collection of surpassed index value. Let’s understand the following example.

Example –

# Pandas Dataframe from Dicts of series.  
  
import pandas as pd  
  
# Initialize data to Dicts of series.  
d = {'Electronics' : pd.Series([97, 56, 87, 45], index =['John', 'Abhinay', 'Peter', 'Andrew']),  
   'Civil' : pd.Series([97, 88, 44, 96], index =['John', 'Abhinay', 'Peter', 'Andrew'])}  
  
# creates Dataframe.  
dframe = pd.DataFrame(d)  
  
# print the data.  
print(dframe)  

Output:

        Electronics      Civil
John             97        97
Abhinay      56        88
Peter           87        44
Andrew      45        96

In this tutorial, we have mentioned the special approaches to create the DataFrames.