Master Python's strptime() for Accurate Date Parsing

Python strptime(): Converting Strings to Datetime Objects

This guide shows how to create datetime objects from strings using Python's datetime.strptime() method, with practical examples and a comprehensive format code reference.

Video: Dates and Times in Python

Watch the official Python tutorial to deepen your understanding of datetime handling.

The strptime() method creates a datetime object from a string that follows a specified format.

Note: Not every string can be parsed; the input must match the format code exactly.

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Example 1: Converting a Simple Date String

from datetime import datetime

date_string = "21 June, 2018"

print("date_string =", date_string)
print("type of date_string =", type(date_string))

date_object = datetime.strptime(date_string, "%d %B, %Y")

print("date_object =", date_object)
print("type of date_object =", type(date_object))

When you run the program, the output will be:

date_string = 21 June, 2018
type of date_string = <class 'str'>
date_object = 2018-06-21 00:00:00
type of date_object = <class 'datetime.datetime'>

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How strptime() Works

The strptime() class method accepts two arguments:

• The string to be parsed.
• The format code that describes the string’s layout.

Based on these inputs, the method returns a datetime object that represents the same moment in time.

In the example above, the format code %d %B, %Y means:

• %d – zero‑padded day of the month (01‑31).
• %B – full month name (January‑December).
• %Y – four‑digit year.

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Example 2: Parsing Ambiguous Dates

from datetime import datetime

dt_string = "12/11/2018 09:15:32"

# Assuming day/month/year format
dt_object1 = datetime.strptime(dt_string, "%d/%m/%Y %H:%M:%S")
print("dt_object1 =", dt_object1)

# Assuming month/day/year format
dt_object2 = datetime.strptime(dt_string, "%m/%d/%Y %H:%M:%S")
print("dt_object2 =", dt_object2)

The program produces:

dt_object1 = 2018-11-12 09:15:32
dt_object2 = 2018-12-11 09:15:32

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Complete List of Format Codes

The table below summarizes all directives you can use with strptime(). For full documentation, refer to Python’s official datetime module guide.

Directive	Meaning	Example
%a	Abbreviated weekday name.	Sun, Mon, ...
%A	Full weekday name.	Sunday, Monday, ...
%w	Weekday as a decimal number.	0, 1, ..., 6
%d	Day of month (zero‑padded).	01, 02, ..., 31
%-d	Day of month (no padding).	1, 2, ..., 30
%b	Abbreviated month name.	Jan, Feb, ..., Dec
%B	Full month name.	January, February, ...
%m	Month number (zero‑padded).	01, 02, ..., 12
%-m	Month number (no padding).	1, 2, ..., 12
%y	Year without century (zero‑padded).	00, 01, ..., 99
%-y	Year without century (no padding).	0, 1, ..., 99
%Y	Year with century.	2013, 2019, ...
%H	Hour (24‑hour clock, zero‑padded).	00, 01, ..., 23
%-H	Hour (24‑hour clock, no padding).	0, 1, ..., 23
%I	Hour (12‑hour clock, zero‑padded).	01, 02, ..., 12
%-I	Hour (12‑hour clock, no padding).	1, 2, ..., 12
%p	Locale’s AM or PM.	AM, PM
%M	Minute (zero‑padded).	00, 01, ..., 59
%-M	Minute (no padding).	0, 1, ..., 59
%S	Second (zero‑padded).	00, 01, ..., 59
%-S	Second (no padding).	0, 1, ..., 59
%f	Microsecond (zero‑padded).	000000 – 999999
%z	UTC offset (+HHMM or –HHMM).
%Z	Time‑zone name.
%j	Day of year (zero‑padded).	001, 002, ..., 366
%-j	Day of year (no padding).	1, 2, ..., 366
%U	Week number (Sunday first).	00, 01, ..., 53
%W	Week number (Monday first).	00, 01, ..., 53
%c	Locale’s date & time.	Mon Sep 30 07:06:05 2013
%x	Locale’s date.	09/30/13
%X	Locale’s time.	07:06:05
%%	A literal percent sign.	%

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Common Error: ValueError

If the string and format code do not match, strptime() raises a ValueError. For example:

from datetime import datetime

date_string = "12/11/2018"
# Incorrect format – expects day month year
date_object = datetime.strptime(date_string, "%d %m %Y")
print("date_object =", date_object)

Running this code produces:

ValueError: time data '12/11/2018' does not match format '%d %m %Y'

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Recommended Reading: Python strftime()