DanielMastCA / stock-analysis

Code Refactoring Analysis of the Stock Analysis Macro

Overview of Project

Our client Steve requires a software to analyze stocks quickly. Using VBA and Excel we have presented Steve with a fully working analysis tool utilizing the data he provided. Steve is wondering how well this program will perform against more extensive databases containing all stock market data from specific years. In this analysis, we take a look at the macro and refactor the code to see if we can make it more efficient.

Results

Refactoring process

In the first version of the macro, we loop over each ticker, find the values in the sheet for that ticker, save the results and so forth.

Original code

'Loops through the tickers
For i = 0 To UBound(tickers)

    'Searches the sheet
    For j = 2 To lastRow
    
        'code
    
    Next j
    
Next i

This proves to be a highly inefficient method as it loops over the whole data set several times until all the tickers are filled. Instead, we went with a simpler and more efficient solution of looping through the dataset once while gathering all the data.

Refactored code

'Searches the sheet
For i = 2 To RowCount
    
    'If ticker matches, then
    If Cells(i - 1, 1) <> tickers(tickerIndex) Then
    
        'code
    
    End If

Next i

Refactoring was a success

After refactoring our code, we recorded the time it took our macro to provide us with the results Steve was looking for. As a result of this refactoring, our macro became significantly faster!

With the data Steve provided, we ran tests on both his 2017 data and his 2018 data.

2017

2018

In both cases, the macro ran significantly faster, cutting the processing time by over 700ms! In conclusion, code refactoring is an essential step in development that can make your code more readable and increase performance.

Summary

What are the advantages or disadvantages of refactoring code?

Refactoring code makes the code easier to understand, more efficient, and easier to maintain, but refactoring code can also be a tedious process, both time and mentality-wise. You can also lose track of what to do, or break something.

How do these pros and cons apply to refactoring the original VBA script?

Refactoring the original VBA script made the analysis faster and increased the script readability, but the code refactoring was time-consuming. Some bugs needed to be solved along the way, and the arrays added into the refactored code made it slightly harder to comprehend.