Append DataFrame to the end of Other DataFrame in Pandas

Append DataFrame to the end of Other DataFrame

To append rows of a DataFrame to the end of this DataFrame, call append() method on this DataFrame and pass the other DataFrame as parameter to this function.

In this tutorial, we will learn the syntax of DataFrame.append() method and how to use this function to append a DataFrame using specified operation(s).

Syntax

The syntax of pandas DataFrame.append() method is

DataFrame.append(other, ignore_index=False, verify_integrity=False, sort=False)

where

Parameter	Value	Description
other	DataFrame or Series/dict-like object, or list of these	The data to append.
ignore_index	bool, default False	If True, the resulting axis will be labeled 0, 1, …, n – 1.
verify_integrity	bool, default False	If True, raise ValueError on creating index with duplicates.
sort	bool, default False	Sort columns if the columns of self and other are not aligned. Changed in version 1.0.0: Changed to not sort by default.

Return Value

DataFrame.

Examples

Append a DataFrame to another DataFrame with Same Index

In the following program, we take a DataFrame and append it using the “other” property, where both the dataframes are given same index.

Example.py

import pandas as pd

df = pd.DataFrame([[1, 2], [3, 4]], columns=list('AB'), index=['x', 'y'])
df2 = pd.DataFrame([[5, 6], [7, 8]], columns=list('AB'), index=['x', 'y'])

result = df.append(df2)
print(result)

Output

   A  B
x  1  2
y  3  4
x  5  6
y  7  8

Append DataFrame Ignoring the Index

In the following program, we take a DataFrame and append it by passing ignore_index =’True’.

Example.py

import pandas as pd

df = pd.DataFrame([[1, 2], [3, 4]], columns=list('AB'), index=['x', 'y'])
df2 = pd.DataFrame([[5, 6], [7, 8]], columns=list('AB'), index=['x', 'y'])

result = df.append(df2, ignore_index=True)
print(result)

Output

   A  B
0  1  2
1  3  4
2  5  6
3  7  8

Generate a DataFrame in a Loop using append() Function

The following program is a less efficient way of generating a dataframe.

Example.py

import pandas as pd

df = pd.DataFrame(columns=['A'])

for i in range(5):
    df = df.append({'A': i}, ignore_index=True)

print(df)  

Output

   A
0  0
1  1
2  2
3  3
4  4

Conclusion

In this Pandas Tutorial, we learned how to append a DataFrame to this DataFrame using pandas DataFrame.append() method.