Python Pandas : How to add rows in a DataFrame using dataframe.append() & lo...

How to add rows in a DataFrame using dataframe.append() & loc[] , iloc[] – thispointer.com

In this article we will discuss how to add a single or multiple rows in a dataframe using dataframe.append() or loc & iloc.

Pandas Dataframe provides a function dataframe.append() i.e.

DataFrame.append(other, ignore_index=False, verify_integrity=False, sort=None)

Here, ‘other’ parameter can be a DataFrame , Series or Dictionary or list of these. Also, if ignore_index is True then it will not use indexes.

Let’s see how to use dataframe.append() to add rows in a dataframe.

First create a dataframe using list of tuples i.e.

# List of Tuples
students = [ ('jack', 34, 'Sydeny' , 'Australia') ,
             ('Riti', 30, 'Delhi' , 'India' ) ,
             ('Vikas', 31, 'Mumbai' , 'India' ) ,
             ('Neelu', 32, 'Bangalore' , 'India' ) ,
             ('John', 16, 'New York' , 'US') ,
             ('Mike', 17, 'las vegas' , 'US')  ]

#Create a DataFrame object
dfObj = pd.DataFrame(students, columns = ['Name' , 'Age', 'City' , 'Country'], index=['a', 'b', 'c' , 'd' , 'e' , 'f']) 

Contents of the dataframe dfObj are,

    Name  Age       City    Country
a   jack   34     Sydeny  Australia
b   Riti   30      Delhi      India
c  Vikas   31     Mumbai      India
d  Neelu   32  Bangalore      India
e   John   16   New York         US
f   Mike   17  las vegas         US

Add row in the dataframe using dataframe.append() and Dictionary

In dataframe.append() we can pass a dictionary of key value pairs i.e.

• key = Column name
• Value = Value at that column in new row

Let’s add a new row in above dataframe by passing dictionary i.e.

# Pass the row elements as key value pairs to append() function 
modDfObj = dfObj.append({'Name' : 'Sahil' , 'Age' : 22} , ignore_index=True)

It will not modify the existing dataframe object dfObj, it will return a new dataframe containing copy of contents of existing dataframe and with a new row appended at it’s end. Contents of the dataframe returned are,

    Name  Age       City    Country
0   jack   34     Sydeny  Australia
1   Riti   30      Delhi      India
2  Vikas   31     Mumbai      India
3  Neelu   32  Bangalore      India
4   John   16   New York         US
5   Mike   17  las vegas         US
6  Sahil   22        NaN        NaN

New DataFrame’s index is not same as original dataframe because ignore_index is passed as True in append() function. Also, for columns which were not present in the dictionary NaN value is added.

Passing ignore_index=True is necessary while passing dictionary or series otherwise following TypeError error will come i.e.

“TypeError: Can only append a Series if ignore_index=True or if the Series has a name”

Add row in the dataframe using dataframe.append() and Series

We can also pass a series to append() to append a new row in dataframe i.e.

# Pass a series in append() to append a row in dataframe  
modDfObj = dfObj.append(pd.Series(['Raju', 21, 'Bangalore', 'India'], index=dfObj.columns ), ignore_index=True)

While creating a series object we pass the index names same as index names of dataframe. Contents of the dataframe returned are,

    Name  Age       City    Country
0   jack   34     Sydeny  Australia
1   Riti   30      Delhi      India
2  Vikas   31     Mumbai      India
3  Neelu   32  Bangalore      India
4   John   16   New York         US
5   Mike   17  las vegas         US
6   Raju   21  Bangalore      India

Add multiple rows in the dataframe using dataframe.append() and Series

We can pass a list of series too in dataframe.append() for appending multiple rows in dataframe.

So, let’s create a list of series with same column names as dataframe i.e.

# List of series  
listOfSeries = [pd.Series(['Raju', 21, 'Bangalore', 'India'], index=dfObj.columns ) ,
                pd.Series(['Sam', 22, 'Tokyo', 'Japan'], index=dfObj.columns ) ,
                pd.Series(['Rocky', 23, 'Las Vegas', 'US'], index=dfObj.columns ) ]

Now pass this list of series to the append() function i.e.

# Pass a list of series to the append() to add multiple rows
modDfObj = dfObj.append(listOfSeries , ignore_index=True)

Contents of the dataframe returned are,

    Name  Age       City    Country
0   jack   34     Sydeny  Australia
1   Riti   30      Delhi      India
2  Vikas   31     Mumbai      India
3  Neelu   32  Bangalore      India
4   John   16   New York         US
5   Mike   17  las vegas         US
6   Raju   21  Bangalore      India
7    Sam   22      Tokyo      Japan
8  Rocky   23  Las Vegas         US

Add a row from one dataframe to other dataframe using dataframe.append()

Let’s create an another dataframe i.e.

# List of Tuples
students = [ ('Rahul', 22, 'Sydeny' , 'Australia') ,
             ('Parul', 23, 'Pune' , 'India')  ]

#Create a DataFrame object
dfObj2 = pd.DataFrame(students, columns = ['Name' , 'Age', 'City' , 'Country'], index=['a', 'b']) 

Contents of this second dataframe objec dfObj2 are,

    Name  Age    City    Country
a  Rahul   22  Sydeny  Australia
b  Parul   23    Pune      India

Now add a row at index ‘b’ from dataframe dfObj2 to dataframe dfObj i.e.

# add row at index b from dataframe dfObj2 to dataframe dfObj
modDfobj = dfObj.append(dfObj2.loc['b'], ignore_index=True)

Contents of the dataframe returned are,

    Name  Age       City    Country
0   jack   34     Sydeny  Australia
1   Riti   30      Delhi      India
2  Vikas   31     Mumbai      India
3  Neelu   32  Bangalore      India
4   John   16   New York         US
5   Mike   17  las vegas         US
6  Parul   23       Pune      India

Add a row in the dataframe using loc[] & list

# Add a new row at index k with values provided in list
dfObj.loc['k'] = ['Smriti', 26, 'Bangalore', 'India']

It will add a new row in dataframe dfObj with index ‘k’ i.e.

     Name  Age       City    Country
a    jack   34     Sydeny  Australia
b    Riti   30      Delhi      India
c   Vikas   31     Mumbai      India
d   Neelu   32  Bangalore      India
e    John   16   New York         US
f    Mike   17  las vegas         US
k  Smriti   26  Bangalore      India

If dataframe already had any row with index name ‘k’ then this will replace the contents of that row, otherwise it will ad new row.

Add a row in the dataframe at index position using iloc[]

# Add a new row at index position 2 with values provided in list
dfObj.iloc[2] = ['Smriti', 26, 'Bangalore', 'India']

It will replace the row at index position 2 in dataframe dfObj with new row i.e.

a    jack   34     Sydeny  Australia
b    Riti   30      Delhi      India
c  Smriti   26  Bangalore      India
d   Neelu   32  Bangalore      India
e    John   16   New York         US
f    Mike   17  las vegas         US
k  Smriti   26  Bangalore      India

Complete example is as follows,

import pandas as pd

def main():
    
    # List of Tuples
    students = [ ('jack', 34, 'Sydeny' , 'Australia') ,
                 ('Riti', 30, 'Delhi' , 'India' ) ,
                 ('Vikas', 31, 'Mumbai' , 'India' ) ,
                 ('Neelu', 32, 'Bangalore' , 'India' ) ,
                 ('John', 16, 'New York' , 'US') ,
                 ('Mike', 17, 'las vegas' , 'US')  ]
    
    #Create a DataFrame object
    dfObj = pd.DataFrame(students, columns = ['Name' , 'Age', 'City' , 'Country'], index=['a', 'b', 'c' , 'd' , 'e' , 'f']) 
    
    print("Original Dataframe" , dfObj, sep='\n')
    

    print("*****Add row in the dataframe using dataframe.append() ****")   

    # Pass the row elements as key value pairs to append() function 
    modDfObj = dfObj.append({'Name' : 'Sahil' , 'Age' : 22} , ignore_index=True)
    
    print("Updated Dataframe" , modDfObj, sep='\n')

    # Pass a series in append() to append a row in dataframe  
    modDfObj = dfObj.append(pd.Series(['Raju', 21, 'Bangalore', 'India'], index=dfObj.columns ), ignore_index=True)

    print("Updated Dataframe" , modDfObj, sep='\n')

    
    print("**** Add multiple rows in the dataframe using dataframe.append() and Series ****")

    # List of series  
    listOfSeries = [pd.Series(['Raju', 21, 'Bangalore', 'India'], index=dfObj.columns ) ,
                    pd.Series(['Sam', 22, 'Tokyo', 'Japan'], index=dfObj.columns ) ,
                    pd.Series(['Rocky', 23, 'Las Vegas', 'US'], index=dfObj.columns ) ]
    
    # Pass a list of series to the append() to add multiple rows
    modDfObj = dfObj.append(listOfSeries , ignore_index=True)

    print("Updated Dataframe" , modDfObj, sep='\n')
    
    
    print("*****Add a row from one dataframe to other dataframe ****") 
    
    # Create an another dataframe 
    # List of Tuples
    students = [ ('Rahul', 22, 'Sydeny' , 'Australia') ,
                 ('Parul', 23, 'Pune' , 'India')  ]
    
    #Create a DataFrame object
    dfObj2 = pd.DataFrame(students, columns = ['Name' , 'Age', 'City' , 'Country'], index=['a', 'b']) 
    
    print("Another Dataframe" , dfObj2, sep='\n')

    # add row at index b from dataframe dfObj2 to dataframe dfObj
    modDfObj = dfObj.append(dfObj2.loc['b'], ignore_index=True)
    
    print("Updated Dataframe" , modDfObj, sep='\n')
    
    print("*****Add a row in the dataframe using loc[] ****")   
    
    # Add a new row at index k with values provided in list
    dfObj.loc['k'] = ['Smriti', 26, 'Bangalore', 'India']
    
    print("Updated Dataframe" , dfObj, sep='\n')
    
    print("*****Add a row in the dataframe at index position using iloc[] ****")
    
    # Add a new row at index position 2 with values provided in list
    dfObj.iloc[2] = ['Smriti', 26, 'Bangalore', 'India']
    
    print("Updated Dataframe" , dfObj, sep='\n')
    
    

    
if __name__ == '__main__':
    main()

Output:

Original Dataframe
    Name  Age       City    Country
a   jack   34     Sydeny  Australia
b   Riti   30      Delhi      India
c  Vikas   31     Mumbai      India
d  Neelu   32  Bangalore      India
e   John   16   New York         US
f   Mike   17  las vegas         US
*****Add row in the dataframe using dataframe.append() ****
Updated Dataframe
    Name  Age       City    Country
0   jack   34     Sydeny  Australia
1   Riti   30      Delhi      India
2  Vikas   31     Mumbai      India
3  Neelu   32  Bangalore      India
4   John   16   New York         US
5   Mike   17  las vegas         US
6  Sahil   22        NaN        NaN
Updated Dataframe
    Name  Age       City    Country
0   jack   34     Sydeny  Australia
1   Riti   30      Delhi      India
2  Vikas   31     Mumbai      India
3  Neelu   32  Bangalore      India
4   John   16   New York         US
5   Mike   17  las vegas         US
6   Raju   21  Bangalore      India
**** Add multiple rows in the dataframe using dataframe.append() and Series ****
Updated Dataframe
    Name  Age       City    Country
0   jack   34     Sydeny  Australia
1   Riti   30      Delhi      India
2  Vikas   31     Mumbai      India
3  Neelu   32  Bangalore      India
4   John   16   New York         US
5   Mike   17  las vegas         US
6   Raju   21  Bangalore      India
7    Sam   22      Tokyo      Japan
8  Rocky   23  Las Vegas         US
*****Add a row from one dataframe to other dataframe ****
Another Dataframe
    Name  Age    City    Country
a  Rahul   22  Sydeny  Australia
b  Parul   23    Pune      India
Updated Dataframe
    Name  Age       City    Country
0   jack   34     Sydeny  Australia
1   Riti   30      Delhi      India
2  Vikas   31     Mumbai      India
3  Neelu   32  Bangalore      India
4   John   16   New York         US
5   Mike   17  las vegas         US
6  Parul   23       Pune      India
*****Add a row in the dataframe using loc[] ****
Updated Dataframe
     Name  Age       City    Country
a    jack   34     Sydeny  Australia
b    Riti   30      Delhi      India
c   Vikas   31     Mumbai      India
d   Neelu   32  Bangalore      India
e    John   16   New York         US
f    Mike   17  las vegas         US
k  Smriti   26  Bangalore      India
*****Add a row in the dataframe at index position using iloc[] ****
Updated Dataframe
     Name  Age       City    Country
a    jack   34     Sydeny  Australia
b    Riti   30      Delhi      India
c  Smriti   26  Bangalore      India
d   Neelu   32  Bangalore      India
e    John   16   New York         US
f    Mike   17  las vegas         US
k  Smriti   26  Bangalore      India

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