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How to Read a CSV File from Amazon S3 Using Python (With Headers and Rows Displayed)

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  Introduction If you’re working with cloud data, especially on AWS, chances are you’ll encounter data stored in CSV files inside an Amazon S3 bucket . Whether you're building a data pipeline or a quick analysis tool, reading data directly from S3 in Python is a fast, reliable, and scalable way to get started. In this blog post, we’ll walk through: Setting up access to S3 Reading a CSV file using Python and Boto3 Displaying headers and rows Tips to handle larger datasets Let’s jump in! What You’ll Need An AWS account An S3 bucket with a CSV file uploaded AWS credentials (access key and secret key) Python 3.x installed boto3 and pandas libraries installed (you can install them via pip) pip install boto3 pandas Step-by-Step: Read CSV from S3 Let’s say your S3 bucket is named my-data-bucket , and your CSV file is sample-data/employees.csv . ✅ Step 1: Import Required Libraries import boto3 import pandas as pd from io import StringIO boto3 is...
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3 Best Methods to Read Files in Python

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Read file line by line

Python supports three specific methods to read files- read, readline, readlines. All these you use on files. Each has its unique purpose. Below are the best examples.

3 Methods to read file

  1. read
  2. readline
  3. readlines

Method-1: read

It reads records from file in sequence.

Here, file.txt is sample file with single row.

file.txt


abcdefghijk

file_object.read(2) ==> you will get 'ab'

file_object.read(4)  ===> you will get 'cdef'


Here, the multiple read methods read the data in sequence. The read(x) method will read only the number of characters that mentioned in the read method. Again, if you give multiple read methods then it will read in sequence.


Method-2: readline


It reads the file line by line.

Here, file.txt is a file with single row.

file.txt

abcdefghijk

file_object.readline() ==> you will get 'abcdefghijk'

Here, it reads the file line by line.


Method-3: readlines

It reads all the records at a time.

Here, file.txt is a file with two rows.

file.txt

abcdefghijk
iiiooooooia

file_object.readlines() ==> you will get both the lines.


abcdefghijk
iiiooooooia

Here, it reads all the lines at a time.

Summary

  • I've demonstrated three methods
  • Useful for interviews and projects

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