There are multiple ways to append two pandas DataFrames, In this article, I will explain how to append two or more pandas DataFrames by using several functions with examples.
In order to append two DataFrames you can use DataFrame.append() method. When you are appending two or more DataFrames, pass all DataFrames as a list to this method.
Alternatively, you can also use pandas.DataFrame.concat() to concatenate DataFrames which can also be used to append two DataFrames.
1. Quick Examples of Append Two DataFrames
If you are in hurry, below are some quick examples of how append two DataFrames in pandas.
# Append two DataFrames
df2 = df.append(df1)
# Using append() with ignore_index
df2 = df.append(df1, ignore_index=True)
# Appending three DataFrames
df3 = df.append([df1, df2], ignore_index=True)
2. Append Two DataFrames
append() is a DataFrame method, meaning if you need to call it on DataFrame. When you want to append two DataFrames, ideally you should be calling this as df2.append(df2)
When you have a different columns on two DataFrames, it appends the column with NaN on the result for rows the same column does not exist. Let’s create a pandas DataFrame from Dict to explore this with an example.
import pandas as pd
df2 = pd.DataFrame({'Courses': ["Spark","PySpark","Python","pandas"],
'Fee' : [20000,25000,22000,24000]})
df2 = pd.DataFrame({'Courses': ["Pandas","Hadoop","Hyperion","Java"],
'Fee': [25000,25200,24500,24900],
'Duration': ['30days','35days','40days','45days']})
# Using append() method
df3 = df1.append(df2)
print(df3)
Yields below output.
# Output:
Courses Fee Duration
0 Spark 20000 NaN
1 PySpark 25000 NaN
2 Python 22000 NaN
3 pandas 24000 NaN
0 Pandas 25000 30days
1 Hadoop 25200 35days
2 Hyperion 24500 40days
3 Java 24900 45days
Using this method you can also append list of rows to the DataFrame.
3. Ignore Index while Append
Append by defaults merges all rows including indices. if you wanted to ignore the index on DataFrames, you can set the new index on the pandas DataFrame by using ignore_index=True param.
# Using append() with ignore_index
df2 = df.append(df1, ignore_index=True)
print(df2)
Yields below output.
# Output:
Courses Fee Duration
0 Spark 20000 NaN
1 PySpark 25000 NaN
2 Python 22000 NaN
3 pandas 24000 NaN
4 Pandas 25000 30days
5 Hadoop 25200 35days
6 Hyperion 24500 40days
7 Java 24900 45days
5. Append Three DataFrames
Similarly, If you have three DataFrames pass all these as a list to the append() method. Use ingore_index=True param to reset the index on pandas DataFrame to start from zero.
# Create third DataFrame
df2 = pd.DataFrame({'Courses':['PHP','GO'],
'Duration':['30day','40days'],
'Fee':[10000,23000]})
# Appending multiple DataFrame
df3 = df.append([df1, df2], ignore_index=True)
print(df3)
Yields below output
# Output:
Courses Fee Duration
Courses Fee Duration
0 Spark 20000 NaN
1 PySpark 25000 NaN
2 Python 22000 NaN
3 pandas 24000 NaN
4 Pandas 25000 30days
5 Hadoop 25200 35days
6 Hyperion 24500 40days
7 Java 24900 45days
8 PHP 10000 30day
9 GO 23000 40days
6. Complete Example of Append Two DataFrames
import pandas as pd
# Complete Example of Append Two DataFrames
df = pd.DataFrame({'Courses': ["Spark","PySpark","Python","pandas"],
'Fee' : [20000,25000,22000,24000]})
df1 = pd.DataFrame({'Courses': ["Pandas","Hadoop","Hyperion","Java"],
'Fee': [25000,25200,24500,24900],
'Duration': ['30days','35days','40days','45days']})
# Using append() method
df2 = df.append(df1)
print(df2)
# Using append() with ignore_index
df2 = df.append(df1, ignore_index=True)
print(df2)
# Create third DataFrame
df2 = pd.DataFrame({'Courses':['PHP','GO'],
'Duration':['30day','40days'],
'Fee':[10000,23000]})
# Appending multiple DataFrame
df3 = df.append([df1, df2], ignore_index=True)
print(df3)
Conclusion
In this artilce you have learned how toappend two DataFrames by examples. Also learned how to append even three DataFrame by passing all DF’s you wanted to append as a list.
Related Articles
- Pandas Concat Two DataFrames Explained
- Pandas Combine Two DataFrames With Examples
- Pandas – Append a List as a Row to DataFrame
- How to Combine Two Series into pandas DataFrame
- How to Append Row to pandas DataFrame
- Pandas Append Rows & Columns to Empty DataFrame
- Pandas append() Usage by Examples
- Append Pandas DataFrames Using for Loop
