.insert()

The .insert() method is used to insert a new column into the DataFrame at the specified location, shifting all existing columns at or above the specified index to the right.

Syntax

DataFrame.insert(loc, column, value, allow_duplicates=False)

• loc: Specifies the index at which the new column is to be inserted. It should be a non-negative integer and must not exceed the current number of columns in the DataFrame.
• column: Provides a string label that describes the newly inserted column.
• value: Represents the content of the inserted column, which can be a scalar, series, or an array-like object. Notably, if a single value is passed, it will be set for all rows in the new column.
• allow_duplicates: A boolean flag that determines whether duplicate column labels are allowed. When set to True, duplicate column labels are permitted, allowing the new column to have the same label as an existing one. Conversely, setting allow_duplicates to False will raise a ValueError if the provided column label matches an existing one.

Example

In the following example, the .insert() method is used with different parameters on the testResults DataFrame:

import pandas as pd

# Creating the DataFrame representing test results administered by Doric
data = {'grade': [99, 76, 64, 83],
        'name': ['Jarnathan', 'Sofina', 'Edgin Darvis', 'Simon the Sorcerer'],
        'home': ['Frozenfar', 'Thay', 'Icewind Dale','Triboar']}

testResults = pd.DataFrame(data)

# Printing the original DataFrame
print("Original Test Results:")
print(testResults)

The output for the above code is as follows:

Original Test Results:
   grade                name          home
0     99           Jarnathan     Frozenfar
1     76              Sofina          Thay
2     64        Edgin Darvis  Icewind Dale
3     83  Simon the Sorcerer       Triboar

Doric forgot to insert the alignment of each person tested. Hence, she uses .insert() to add the alignment of each person:

import pandas as pd

data = {'grade': [99, 76, 64, 83],
        'name': ['Jarnathan', 'Sofina', 'Edgin Darvis', 'Simon the Sorcerer'],
        'home': ['Frozenfar', 'Thay', 'Icewind Dale','Triboar']}

testResults = pd.DataFrame(data)

# Inserting a new column
testResults.insert(3, 'alignment', ['Lawful Good','Neutral Evil','Chaotic Good','Chaotic Good'])

# Printing the updated DataFrame
print("Updated Test Results:")
print(testResults)

The above code produces the following output:

Updated Test Results:
   grade                name          home     alignment
0     99           Jarnathan     Frozenfar   Lawful Good
1     76              Sofina          Thay  Neutral Evil
2     64        Edgin Darvis  Icewind Dale  Chaotic Good
3     83  Simon the Sorcerer       Triboar  Chaotic Good

Szass Tam used scrying to learn Doric’s password. To confuse Doric, Szass decided to add an identical grade column as follows:

import pandas as pd

data = {'grade': [99, 76, 64, 83],
        'name': ['Jarnathan', 'Sofina', 'Edgin Darvis', 'Simon the Sorcerer'],
        'home': ['Frozenfar', 'Thay', 'Icewind Dale','Triboar']}

testResults = pd.DataFrame(data)

testResults.insert(3, 'alignment', ['Lawful Good','Neutral Evil','Chaotic Good','Chaotic Good'])

# Inserting a new column
testResults.insert(1, 'grade', [54,100,26,70],allow_duplicates=True)

# Printing the updated DataFrame
print("Updated Test Results:")
print(testResults)

Here is the output for the above code:

Updated Test Results:
   grade  grade                name          home     alignment
0     99     54           Jarnathan     Frozenfar   Lawful Good
1     76    100              Sofina          Thay  Neutral Evil
2     64     26        Edgin Darvis  Icewind Dale  Chaotic Good
3     83     70  Simon the Sorcerer       Triboar  Chaotic Good

Codebyte Example

The following example demonstrates the use of the .insert() method in Pandas to add a new column named alignment to a DataFrame, representing alignment information for test results:

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