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Articles by SaiKrishna Tavva
Page 2 of 8
How to prepare a Python date object to be inserted into MongoDB?
We can use the PyMongo library (the official Mongodb driver for Python) to connect to a Mongodb database and use it to insert, update, delete, etc objects. To include date and time information, Mongodb supports ISODate format, and PyMongo provides direct support for Python's datetime.datetime objects. There are multiple ways to prepare a Python date object for insertion into MongoDB, which we will discuss here: Create and Insert Date Object to MongoDB Using datetime.datetime.utcnow() The simplest way to create a Python date object that can be inserted into MongoDB is by using datetime.datetime.utcnow() from the datetime module. You can use ...
Read MoreHow to compare calendar.timegm() vs. time.mktime() in Python?
In Python, the mktime() function (from the time module) assumes that the passed tuple is in local time, while the calendar.timegm() (from the calendar module) assumes it's in GMT/UTC. Depending on the interpretation, the tuple represents a different time, so both functions return different values (seconds since the epoch are UTC-based). The difference between the values should be equal to the time zone offset of your local time zone. Understanding time.mktime() in Local Time Context The Python time.mktime() method converts the object form of local time into seconds since the epoch (January 1, 1970, 00:00:00 UTC). This method is the inverse function of localtime() and ...
Read MoreHow does nested character class subtraction work in Python?
Nested character class subtraction in Python's regular expressions allows us to define complex character sets by removing characters from an existing character class, including another character class by using the '-' operator. It works from the innermost to outermost character class, and subtractions are evaluated from left to right within the square brackets [ ]. Usually, Python's library, re, doesn't directly support nested character class subtraction like some other regex engines do. We can't write something like [[abc]-[bc]], which means characters a, b, or c, excluding b or c. So we need to install a third-party module like regex ...
Read MoreWhat are negated character classes that are used in Python regular expressions?
While working with Python regex, if we want to match everything except certain characters, then we can use negated character classes by placing a caret (^) as the first character inside square brackets. The pattern [^abdfgh] will match any character not in that set. What is a Negated Character Class? A character class like [abc] matches any single character except 'a', 'b', or 'c'. But if we use a ^ symbol at the beginning, like [abc], it will match any character except 'a', 'b', or 'c'. This allows us to eliminate certain characters from the match quickly. The position of ...
Read MoreWhich one is more accurate in between time.clock() vs. time.time()?
Two commonly used functions from the Python time module are time.time() and time.clock(). Each function provides a different purpose and returns different values depending on the platform (Windows vs. Unix). In Python 3.8, time.clock() was removed, so time.perf_counter() or time.process_time() are generally preferred over the older time.clock() for specific CPU time measurements. The time.clock() was designed for measuring process CPU time, while time.time() measures wall-clock time. The time.time() is more accurate for measuring overall elapsed time ( the duration of time that has passed between two specific points in time). Measuring Elapsed Time with time.time() The time.time() function returns the number of ...
Read MoreHow to convert timestamp string to datetime object in Python?
In many real-world applications, timestamps are used to represent dates and times, but they are not human-readable. To make them understandable or use them in various datetime manipulations, it’s essential to convert them into Python’s datetime object. Python’s datetime module provides multiple functions to convert timestamps to datetime objects. Below are the various methods to accomplish this task - Using datetime.fromtimestamp() Function Using datetime.fromtimestamp() & strftime() Using datetime.strptime() Function Parsing Mixed Text Using strptime() Function Using datetime.fromtimestamp() Function To obtain a date ...
Read MoreHow to pass a json object as a parameter to a python function?
We can pass a JSON object as a parameter to a Python function using the json.loads() method. we can also convert the JSON string into a Python dictionary or list, which depends on its structure. Once converted, the data can be used just like any other dictionary or list in Python. JSON Object Consider a JSON object to pass to a python function. We will use it further in this article - { "name":"Rupert", "age": 25, "desig":"developer" } Using json.loads() Function Before passing a JSON object as a parameter ...
Read MoreHow can you execute functions with multiple arguments at a terminal?
In Python, you can execute functions with multiple arguments directly from the terminal using different approaches depending on how your function is defined and how you want to provide the arguments. Executing Python functions from the terminal allows you to quickly test or run code without writing a full script. When a function requires multiple arguments, you can pass them manually, use input prompts, or use command-line arguments with the help of modules like sys or argparse. Using the Python Interactive Shell If you are working in the Python interactive shell, you can define and call functions directly by entering ...
Read MoreHow to match whitespace but not newlines using Python regular expressions?
In Python, regular expressions (regex) search and manipulate strings in various ways. If we need to match whitespace characters without including newline characters. This article will explore how to achieve this using Python’s re module. The following are the methods included to match whitespace but not newlines using Python regular expressions - Using re.sub() Method Using re.findall() Method Using Positive Lookahead Using re.sub() Method The re.sub() method offers an efficient way to replace whitespace characters (excluding newlines) within a string. This method takes the pattern ...
Read MoreHow you can get a true/false from a Python regular expressions?
The re module provides tools while working with Python's regular expression (regex), which allows us to search for any specific pattern within the strings. Using the 're' module provides two functions named match() and search(), which accept a pattern (regular expression) and return True or False. The match() function returns 'None' if no pattern is detected, or it returns the match in the form of an object (in case of a match). In addition to these, we can also use the fullmatch() function to get a boolean result from a regular expression. ...
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