Example 1: how to add a column to a pandas df
#using the insert function:
df.insert(location, column_name, list_of_values)
#example
df.insert(0, 'new_column', ['a','b','c'])
#explanation:
#put "new_column" as first column of the dataframe
#and puts 'a','b' and 'c' as values
#using array-like access:
df['new_column_name'] = value
#df stands for dataframe
Example 2: python how to add columns to a pandas dataframe
# Basic syntax:
pandas_dataframe['new_column_name'] = ['list', 'of', 'column', 'values']
# Note, the list of column values must have length equal to the number
# of rows in the pandas dataframe you are adding it to.
# Add column in which all rows will be value:
pandas_dataframe['new_column_name'] = value
# Where value can be a string, an int, a float, and etc
Example 3: add column to df from another df
# pre 0.24
feature_file_df['RESULT'] = RESULT_df['RESULT'].values
# >= 0.24
feature_file_df['RESULT'] = RESULT_df['RESULT'].to_numpy()
Example 4: how to add new column to dataframe
# Import pandas package
import pandas as pd
# Define a dictionary containing Students data
data = {'Name': ['Jai', 'Princi', 'Gaurav', 'Anuj'],
'Height': [5.1, 6.2, 5.1, 5.2],
'Qualification': ['Msc', 'MA', 'Msc', 'Msc']}
# Convert the dictionary into DataFrame
df = pd.DataFrame(data)
# Declare a list that is to be converted into a column
address = ['Delhi', 'Bangalore', 'Chennai', 'Patna']
# Using 'Address' as the column name
# and equating it to the list
df['Address'] = address
# Observe the result
df
Example 5: how to add a new column to the pandas df
import pandas as pd
data = {'Name': ['Josh', 'Stephen', 'Drake', 'Daniel'],
'Height': [5.5, 6.0, 5.3, 4.9]}
'''
printing data at this point will show the following
Name Height
0 Josh 5.1
1 Stephen 6.2
2 Drake 5.1
3 Daniel 5.2
'''
df.insert(2, "Age", [20, 21, 20, 19])
'''
printing data now will show the following
Name Height Age
0 Josh 5.1 20
1 Stephen 6.2 21
2 Drake 5.1 20
3 Daniel 5.2 19
'''