In this article, we will discuss how to get a list of specified column of a Pandas Dataframe. First, we will read a csv file into a pandas dataframe.
Note: To get the CSV file used click here.
Creating the DataFrame
Python3
# importing pandas moduleimport pandas as pd # making data frame from csvdata = pd.read_csv("nba.csv") # calling head() method df = data.head(5) # displaying datadf |
Output:
Get a list of a specified column of a Pandas
Let’s see how to get a list of a specified column of a Pandas DataFrame:
We will convert the column “Name” into a list.
Using series.tolist() to get a list of a specified column
From the dataframe, we select the column “Name” using a [] operator that returns a Series object. Next, we will use the function Series.to_list() provided by the Series class to convert the series object and return a list.
Python3
# importing pandas moduleimport pandas as pd# making data frame from csvdata = pd.read_csv("nba.csv")df = data.head(5)# Converting a specific Dataframe# column to list using Series.tolist()Name_list = df["Name"].tolist()print("Converting name to list:")# displaying listName_list |
Output:
Get a list of a specified column of a Pandas
Let’s break it down and look at the types
Python3
# column 'Name' as series objectprint(type(df["Name"]))# Convert series object to a listprint(type(df["Name"].values.tolist() |
Output:
Get a list of a specified column of a Pandas
Using numpy.ndarray.tolist() to get a list of a specified column
With the help of numpy.ndarray.tolist(), dataframe we select the column “Name” using a [] operator that returns a Series object and uses Series.Values to get a NumPy array from the series object. Next, we will use the function tolist() provided by NumPy array to convert it to a list.
Python3
# Converting a specific Dataframe column# to list using numpy.ndarray.tolist()Name_list = df["Name"].values.tolist()print("Converting name to list:")# displaying listName_list |
Output:
Get a list of a specified column of a Pandas
Similarly, breaking it down
Python3
# Select a column from dataframe# as series and get a numpy arrayprint(type(df["Name"].values))# Convert numpy array to a listprint(type(df["Name"].values.tolist() |
Output:
Get a list of a specified column of a Pandas
Using Python list() function to get a list of a specified column
You can also use the Python list() function with an optional iterable parameter to convert a column into a list.
Python3
Name_List = list(df["Name"])print("Converting name to list:")# displaying listName_List |
Output:
Get a list of a specified column of a Pandas
Converting index column to list
Index column can be converted to list, by calling pandas.DataFrame.index which returns the index column as an array and then calling index_column.tolist() which converts index_column into a list.
Python3
# Converting index column to listindex_list = df.index.tolist()print("Converting index to list:")# display index as listindex_list |
Output:
Get a list of a specified column of a Pandas
