#### Overview of this book

If you want to find out how you can build a solid foundation in algorithmic trading using Python, this cookbook is here to help. Starting by setting up the Python environment for trading and connectivity with brokers, you’ll then learn the important aspects of financial markets. As you progress, you’ll learn to fetch financial instruments, query and calculate various types of candles and historical data, and finally, compute and plot technical indicators. Next, you’ll learn how to place various types of orders, such as regular, bracket, and cover orders, and understand their state transitions. Later chapters will cover backtesting, paper trading, and finally real trading for the algorithmic strategies that you've created. You’ll even understand how to automate trading and find the right strategy for making effective decisions that would otherwise be impossible for human traders. By the end of this book, you’ll be able to use Python libraries to conduct key tasks in the algorithmic trading ecosystem. Note: For demonstration, we're using Zerodha, an Indian Stock Market broker. If you're not an Indian resident, you won't be able to use Zerodha and therefore will not be able to test the examples directly. However, you can take inspiration from the book and apply the concepts across your preferred stock market broker of choice.

# Modifying datetime objects

Often, you may want to modify existing datetime objects to represent a different date and time. This recipe includes code to demonstrate this.

## How to do it…

Follow these steps to execute this recipe:

1. Import the necessary modules from the Python standard library:
`>>> from datetime import datetime`
1. Fetch the current timestamp. Assign it to dt1 and print it:
`>>> dt1 = datetime.now()>>> print(dt1)`

We get the following output. Your output would differ:

`2020-08-12 20:55:46.753899`
1. Create a new datetime object by replacing the year, month, and day attributes of dt1. Assign it to dt2 and print it :
`>>> dt2 = dt1.replace(year=2021, month=1, day=1)>>> print(f'A timestamp from 1st January 2021: {dt2}')`

We get the following output. Your output would differ:

`A timestamp from 1st January 2021: 2021-01-01 20:55:46.753899`
1. Create a new datetime object by specifying all the attributes directly. Assign it to dt3...