Writing CSV files in Python

Assume the learner will use the built-in csv module and basic file operations.

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1) Create Simple CSV

Write a CSV file students.csv with:

name,age
Alice,20
Bob,22

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2) Write with Header Only

Create products.csv with headers only:

id,product,price

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3) Write 3 Rows

Ask the user for 3 product entries (id, product, price) and write them to products.csv.

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4) Append a Row

Write code that appends this row to an existing CSV:

Charlie,25,Vancouver

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5) Write List of Lists

Given a list:

data = [
    ["John", "30"],
    ["Jane", "27"],
    ["Jake", "25"]
]

Write it to people.csv with header name,age.

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6) Write Using DictWriter

Create employees.csv with fields name,dept,salary, and write 3 dictionary rows using csv.DictWriter.

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7) Write with Fieldnames from User

Ask user for column names (comma-separated) and create header in a new CSV.

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8) Write Numeric Data

Create scores.csv with:

subject,score
Math,90
English,85
Science,92

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9) Write Mixed Data Types

Write a CSV where one column is text and one is number.

Example row:

Item,Stock
Pens,50

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10) Write Multiple CSV Files

Ask the user for n, then write n CSV files named file1.csv, file2.csv, …, each with sample data.

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11) Write with Quoting

Write a CSV where fields are quoted even if not necessary (use quoting options).

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12) Write with Tab Delimiter

Write a file tabdata.csv where columns are separated by tabs instead of commas.

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13) Predefined Header + Rows

Write a CSV countries.csv with:

country,capital
Canada,Ottawa
USA,Washington
India,New Delhi

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14) Write CSV Using writerow in Loop

Ask for 5 names and write them one per line with a serial number.

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15) Write and Read Back

Create a CSV, then immediately open it and print its contents in the same script.

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16) Write to CSV from a List of Dicts

Given:

data = [
    {"name":"Sam","age":28},
    {"name":"Sara","age":24}
]

Write it to people2.csv.

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17) Append With DictWriter

Add a new employee row to employees.csv using DictWriter in append mode.

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18) Save Strings as Rows

Given a list of strings like:

["apple", "banana", "cherry"]

Write each as a separate row in fruits.csv.

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19) Write CSV with Computed Values

Ask user for numbers, compute squares, and write pairs in CSV.

Example CSV:

number,square
2,4
3,9

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20) Write CSV with Random Data

Generate 10 random integers and write them to random.csv with columns:

index,value
0,<random>
1,<random>
… 

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🧠 Functions / Modules You’ll Use

Task	Module / Method
Write CSV	csv.writer
Write with header	csv.writer / writerow()
Write dicts	csv.DictWriter, writeheader()
Append rows	open file in "a" mode
Quoting	csv.QUOTE_ALL
Custom delimiter	csv.writer(..., delimiter="\t")

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📌 Starter Code Snippet (Basic Writer)

import csv

with open("students.csv","w",newline="") as f:
    writer = csv.writer(f)
    writer.writerow(["name","age"])
    writer.writerow(["Alice","20"])
    writer.writerow(["Bob","22"])

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📌 DictWriter Example

import csv

with open("employees.csv","w",newline="") as f:
    fieldnames = ["name","dept","salary"]
    writer = csv.DictWriter(f, fieldnames=fieldnames)
    writer.writeheader()
    writer.writerow({"name":"Sam","dept":"HR","salary":"50000"})

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canvil: 333f6c7d-6876-4f7e-b6ad-1bdb2233f5c1