What are your go-to techniques for cleaning large data sets before analysis, and why do you prefer them?

I personally follow these steps in excel for cleaning all data set

1. Define a Key : When dealing with large data sets, define a column which will always have unique enteries and define that column as your key identifier

2. Delete Duplciates : Based on this key entry, apply the conditional formatting to first highlight duplicates. Spend few minutes on comparing the data of duplicates against same key. If the data is same, delete the duplicate enteries using excel "delete duplicates" operation

3. Define Headers: Properly Rename the headers of each column and delete any unwanted columns.

4. Formatting: Go through each column and confirm that it is formatted in right manner. For example if some column contain dates, format that column as short date. If some column as decimal places, you can truncate them till 2 decimal places to make all of them uniform

5. Convert into Table: Formatting your large data into table will save a lot of your time and operations. You will be able to filter your data, sort your data and search your data in the easiest way possible. Moreover when adding new rows, formatting will remain intact. You can also use slicers in the later stage when dealing with tabular data.

My go-to techniques for cleaning large data sets include:

Removing Duplicates: Ensures unique data entries, reducing redundancy.

Handling Missing Data: Using imputation, deletion, or placeholder values based on the dataset's context.

Standardizing Formats: Aligns data units, date formats, and text case for consistency.

Filtering Outliers: Identifies and manages outliers that could skew analysis.

Data Validation Rules: Prevents entry errors by enforcing constraints.

Data Type Conversion: Ensures numeric, categorical, or textual data are correctly formatted.

These techniques enhance data quality, reliability, and accuracy, ensuring meaningful and actionable insights during analysis.

There is a large variety to tools available from excel macros to Python. it depends on the type of data. quality and quantity of data. I usually use microsoft excel .