Professional data cleaning on a historical dataset β removing duplicates, fixing date formats, standardizing party names using TRIM and text functions.
4 types
Duplicates, dates, whitespace, formatting
45
US Presidents
1 removed
Woodrow Wilson
SerialβDate
Excel serials converted
Data Issues Found & Fixed
Before vs After cleaning β each issue type
Before Cleaning β Raw Data Issues
Problems identified in original dataset
β Issues Found
β Duplicate row: Woodrow Wilson (row 28 & 29)
β Date stored as Excel serial: 44756 instead of 14-Jul-21
β Party names with extra spaces: "Democratic- Republican"
β Inconsistent capitalization in party column
β Trailing whitespace in president names
After Cleaning β Fixed Data
Techniques applied in Excel
β Fixes Applied
β Removed duplicate using: Remove Duplicates tool
β Fixed dates using: TEXT(A2,"DD-MMM-YY")
β Trimmed whitespace: =TRIM(party_column)
β Standardized party names: =PROPER(TRIM(A2))
β Documented all steps for reproducibility
Party Distribution β After Cleaning
Clean political party breakdown across 45 presidents
Advanced Excel Formulas
XLOOKUP, INDEX/MATCH, IF/IFS, SUMIF, COUNTIF and more β demonstrated on the Dunder Mifflin HR dataset.