Python File HandlingMind map · Lesson 7 of 7

Python CSV Module in Hindi – Mind Map

Everything this lesson covers — Module Setup & Basics, CSV Reader (List-based), CSV Writer (List-based), CSV DictReader (Dictionary-based), CSV DictWriter (Dictionary-based) and File Opening Modes — in one visual map. Click any topic to open it, or download the full map as an image for revision.

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Mind map

Python CSV File Handling

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Python CSV Module in Hindi: lesson notes

01Module Setup & Basics
- Previous Modules Recap
  - Pathlib methods: path, exists(), is_file(), is_dir(), mkdir(), rename()
  - OS module
- Importing Libraries
  - import csv
  - from pathlib import Path
  - import os
- Common File Parameters
  - with open('file.csv', 'mode', newline='') as file:
  - newline='' for CSV handling
02CSV Reader (List-based)
- Creating Reader Object
  - reader = csv.reader(file)
  - Returns a reader object
- Reading Data
  - for row in reader: print(row)
  - Rows returned as lists of strings
- Accessing Elements
  - row[index] for column data
- Skipping Header
  - next(reader) to advance iterator
03CSV Writer (List-based)

Creating Writer Object
- writer = csv.writer(file)
Writing Single Row
- writer.writerow(['col1', 'col2'])
- Writes a list as one row
Writing Multiple Rows
- data = [['a', 1], ['b', 2]]
- writer.writerows(data)
- Writes a list of lists

04CSV DictReader (Dictionary-based)

Creating DictReader Object
- reader = csv.DictReader(file)
- Returns a DictReader object
Reading Data
- for row in reader: print(row)
- Rows returned as dictionaries
Accessing Elements
- row['header_key'] for column data
Example: Filtering by Marks
- marks = int(row['marks'])
- if marks > 90: print(row['name'], marks)

05CSV DictWriter (Dictionary-based)

Creating DictWriter Object
- fieldnames = ['name', 'age', 'course']
- writer = csv.DictWriter(file, fieldnames=fieldnames)
Writing Header
- writer.writeheader()
- Uses fieldnames for header
Writing Single Row
- writer.writerow({'name': 'John', 'age': 30})
- Writes a dictionary as one row
Writing Multiple Rows
- data = [{'name': 'Jane', 'age': 25}]
- writer.writerows(data)
- Writes a list of dictionaries
User Input Example
- Prompt for number of students
- Loop to collect name, age, marks
- Create dictionary for each student
- Append to list, then writerows()

06File Opening Modes

r: Read only, file must exist
w: Write only, overwrites, creates
a: Append only, adds to end, creates
r+: Read/write, file must exist
w+: Write/read, overwrites, creates
a+: Append/read, adds to end, creates

Python CSV Module in Hindi – Mind Map

Python CSV File Handling

Python CSV Module in Hindi: lesson notes

01Module Setup & Basics

Previous Modules Recap

Importing Libraries

Common File Parameters

02CSV Reader (List-based)

Creating Reader Object

Reading Data

Accessing Elements

Skipping Header

03CSV Writer (List-based)

Creating Writer Object

Writing Single Row

Writing Multiple Rows

04CSV DictReader (Dictionary-based)

Creating DictReader Object

Reading Data

Accessing Elements

Example: Filtering by Marks

05CSV DictWriter (Dictionary-based)

Creating DictWriter Object

Writing Header

Writing Single Row

Writing Multiple Rows

User Input Example

06File Opening Modes

r: Read only, file must exist

w: Write only, overwrites, creates

a: Append only, adds to end, creates

r+: Read/write, file must exist

w+: Write/read, overwrites, creates

a+: Append/read, adds to end, creates