How To Retrieve A Specific Element In A Csv File?

A CSV (comma-separated values) file is a text file with comma-separated values. They are used in data science and machine learning to represent the dataset. They are used in business applications to manage large amounts of data. Information in the CSV file can be represented in a tabular form with rows and columns. The CSV file uses UTF-8 encoding.NULL or missing values are represented using an empty field or with “NaN”.It does not support macros, styling, formulas, or calculations.

In this article, we will learn how to retrieve a specific element from a CSV file. A specific element in the CSV file is associated with the column name and the row number. To get the specific element, we can use an iterative method or the element index. Different languages, such as Python, Java, or Node.js are used to retrieve the specific element.

How do I retrieve a specific element from a CSV file?

To retrieve the specific element from the CSV file, we need to have information about the CSV file. Information like header contents and number of rows in the file. We can use an iterative method or the element index to retrieve the specific element.

The CSV file used is StudentPerformance.CSV.Contents of the file are

gender,race/ethnicity,parental level of education,lunch,test preparation course,math score,reading score,writing score
female,group B,bachelor's degree,standard,none,72,72,
female,group C,some college,standard,completed,69,90,88
female,group B,master's degree,standard,none,90,95,93
male,group A,associate's degree,free/reduced,none,47,57,44
male,group C,some college,standard,none,76,78,75
female,group B,associate's degree,standard,none,71,83,78
female,group B,some college,standard,completed,88,95,92
male,group B,some college,free/reduced,none,40,43,39

Method 1: Using the Pandas library.

Python supports different libraries; Pandas is one of them. Pandas Library supports different methods that are used for preprocessing data, handling missing data, slicing data, filtering, and indexing the data. Here are steps to retrieve the specific element:

Step 1: Import pandas library

It is the initial step through which the pandas’ library is imported.

Python

# code
import pandas as pd

Step 2: Read the CSV file.

In this step, the CSV file is read using the read_csv() method which is supported by pandas. The read file is stored in the DataFrame. File location should be always mentioned in the read_csv() method, it can also have different arguments.

Python3

df = pd.read_csv(
    "https://media.geeksforgeeks.org/wp-content/uploads/20240206150437/StudentPerformance.csv")
print(df.head())

Output:

   gender race/ethnicity parental level of education         lunch  \
0  female        group B           bachelor's degree      standard   
1  female        group C                some college      standard   
2  female        group B             master's degree      standard   
3    male        group A          associate's degree  free/reduced   
4    male        group C                some college      standard   
  test preparation course  math score  reading score  writing score  
0                    none          72             72            NaN  
1               completed          69             90           88.0  
2                    none          90             95           93.0  
3                    none          47             57           44.0  
4                    none          76             78           75.0  

Step 3: Retrieve the specific element

In this step specific element is retrieved based on the label. Pandas support the .loc attribute which uses label-based indexing on the DataFrame.Dataframe is a two-dimensional, tabular data structure in Pandas.

Python3

element = df.loc[3, "gender"]
print('Element at 3+1=4th rows of gender column :', element)

# or using iloc
element2 = df.iloc[3, 3]
print('Element at 3+1=4th rows rows of 3+1=4th column :', element2)

Output:

Element at 3+1=4th rows of gender column : male
Element at 3+1=4th rows rows of 3+1=4th column : free/reduced

Initially, pandas library is imported and csv file is read. It is stored in a data frame and the .loc attribute is used to retrieve the gender of the index 3. The value of the 3 index is printed at last.

Method 2: Defining a function

Python3

import csv

def retrieve_csv_element(csv_file_path, row_index, column_index):
    try:
        # Read the CSV file
        with open(csv_file_path, 'r') as csv_file:
            # Create a CSV reader object
            csv_reader = csv.reader(csv_file)

            # Iterate through the rows
            for current_row_index, row in enumerate(csv_reader):
                # Check if the current row matches the desired row index
                if current_row_index == row_index:
                    # Check if the current row has enough columns
                    if column_index < len(row):
                        # Retrieve the specific element and return it
                        return row[column_index]
                    else:
                        raise ValueError(
                            f"Column index {column_index} is out of range for row {row_index}")

            # If the desired row index is not found
            raise ValueError(
                f"Row index {row_index} not found in the CSV file")

    except Exception as e:
        print(f"An error occurred: {e}")

Retrieve A Specific Element

Python3

# Example usage
csv_file_path = "StudentPerformance.csv"

row_index = 4
column_index = 0

element = retrieve_csv_element(csv_file_path, row_index, column_index)
if element is not None:
    print(f"Element at row {row_index}, column {column_index}: {element}")

Output:

Element at row 4, column 0: male

Conclusion

In this article, we have used python libraries and defined a python function to retrieve a specific element from a CSV file. We have learned how to retrieve the specific element from the CSV file.