Python Profiling — Why and Where Your Code is Slow

<p>Picture this: you write a script to process some data on your laptop, go for a coffee break, and when you return in 15 minutes, it’s barely 10% done.</p> <p>Why is it so slow? Which part is slow? Is it reading the data, processing it, or saving it? How do I make it faster?<em> Is it even actually slow?</em></p> <p>A tool called profiler will help you answer all of these questions.</p> <h1>What Is a Profiler?</h1> <p>A profiler is a tool that takes your code, runs it, and collects information about how much time each function call takes, how many times has it been executed, and the hierarchy of function calls.</p> <p>And by analyzing its output, you can find out which part of your code takes the most time to execute (called bottleneck) and maybe even come up with an idea on how to do that. You want to identify and resolve bottlenecks, which leads to the largest speed improvements overall.</p> <h1>Example Problem</h1> <p>Let’s say we have a large text file, and we want to find several occurrences of a certain pattern in it. First, let’s generate a large file of random alphanumeric characters (line by line):</p> <p><a href="https://betterprogramming.pub/python-profiling-why-and-where-your-code-is-slow-d6f41601dba8">Click Here</a></p>