Python strftime()

1. What is strftime()

strftime() converts a datetime object into a formatted string based on specified format codes.

from datetime import datetime

now = datetime.now()
formatted = now.strftime("%Y-%m-%d")
print(formatted)  # e.g., 2025-11-24

It is essential for displaying dates in human-readable formats, logs, and reports.

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2. Basic Date Formatting

from datetime import datetime

now = datetime.now()

print(now.strftime("%d/%m/%Y"))  # Day/Month/Year
print(now.strftime("%m-%d-%Y"))  # Month-Day-Year

Customizes how date appears in different regional formats.

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3. Time Formatting

from datetime import datetime

now = datetime.now()

print(now.strftime("%H:%M:%S"))  # 24-hour format
print(now.strftime("%I:%M %p"))  # 12-hour format with AM/PM

Used for clock displays and timestamping.

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4. Including Day and Month Names

from datetime import datetime

now = datetime.now()

print(now.strftime("%A"))  # Full weekday name
print(now.strftime("%a"))  # Short weekday name
print(now.strftime("%B"))  # Full month name
print(now.strftime("%b"))  # Short month name

Enhances readability in user-facing outputs.

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5. Combining Date and Time

from datetime import datetime

now = datetime.now()

print(now.strftime("%Y-%m-%d %H:%M:%S"))

Common format for logs and system monitoring.

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6. Using strftime() for File Naming

from datetime import datetime

filename = "backup_" + datetime.now().strftime("%Y%m%d_%H%M%S") + ".zip"
print(filename)

Ideal for generating timestamped files safely.

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7. ISO 8601 Format Using strftime

from datetime import datetime

now = datetime.now()
iso_format = now.strftime("%Y-%m-%dT%H:%M:%S")
print(iso_format)

Used in APIs and structured data exchange.

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8. Custom Human-Readable Format

from datetime import datetime

now = datetime.now()

print(now.strftime("Today is %A, %d %B %Y at %I:%M %p"))

Creates expressive, user-friendly messages.

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9. Formatting Specific datetime Object

from datetime import datetime

custom_date = datetime(2025, 12, 25, 18, 30)

print(custom_date.strftime("%A, %d %B %Y - %H:%M"))

Formats fixed or scheduled execution dates.

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10. Enterprise Use Case: Log Timestamp

from datetime import datetime

def log_message(message):
    timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    print(f"[{timestamp}] {message}")

log_message("Server started")
log_message("User authenticated")

Standard pattern for production logging and auditing systems.

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Common strftime() Format Codes

Code	Description	Example
%Y	Full year	2025
%y	Short year	25
%m	Month (01-12)	11
%d	Day (01-31)	24
%H	Hour (24h)	19
%I	Hour (12h)	07
%M	Minute	45
%S	Second	59
%p	AM/PM	PM
%A	Weekday	Monday
%B	Month name	November

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Summary

strftime() is a foundational tool for:

• Formatting logs

• Generating reports

• File versioning

• Time-based automation

• User-interface display strings

It provides complete flexibility for representing date and time values.

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