Compute the factor of a given array by Singular Value Decomposition using NumPy

Extract date from a specified column of a given Pandas DataFrame using Regex

Last Updated : 29 Aug, 2020

In this article, we will discuss how to extract only valid date from a specified column of a given Data Frame. The extracted date from the specified column should be in the form of ‘mm-dd-yyyy’.

Approach:

In this article, we have used a regular expression to extract valid date from the specified column of the data frame. Here we used \b(1[0-2]|0[1-9])/(3[01]|[12][0-9]|0[1-9])/([0-9]{4})\b this regular expression. We’ll be using re.findall() method for this. Now let us try to implement this using Python:

Step 1: Creating Dataframe

Python3

# importing pandas and re library 
import pandas as pd 
import re as re 
  
# creating data frame with column 
# name,date_of_birth and age 
df = pd.DataFrame({'Name': ['Akash', 'Shyam', 'Ayush', 
                            'Diksha', 'Radhika'], 
  
                   'date_of_birth': ['12/21/1998', '15/12/1998', 
                                     '06/11/2000', '05/10/1998', 
                                     '13/12/2010'], 
  
                   'Age': [21, 12, 20, 21, 10]}) 
  
# printing the original data frame 
print("Printing the original dataframe") 
df 

Output:

Step 2: Extracting valid date from data frame in the format ‘mm-dd-yyyy’

Python3

# creating function to find whether the  
# given date is valid or not 
def checking_valid_dates(dt): 
      
    # creating regular expression to check  
    # whether date fall in the format  
    # mm-dd-yyyy 
    result = re.findall( 
        r'\b(1[0-2]|0[1-9])/(3[01]|[12][0-9]|0[1-9])/([0-9]{4})\b', dt) 
    return result 
  
  
# creating new column with valid_date_of_birth 
df['valid_date_of_birth'] = df['date_of_birth'].apply( 
    lambda dt: checking_valid_dates(dt)) 
  
print("\nPrinting the data frame Valid dates in the format: mm-dd-yyyy:") 
df 

Output:

Compute the factor of a given array by Singular Value Decomposition using NumPy

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