SQL - SELECT DISTINCT with Examples
SELECT DISTINCT filters duplicate rows from your result set. The operation examines all columns in your SELECT clause and returns only unique combinations.
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R dplyr - distinct() - Remove Duplicates
The distinct() function from dplyr identifies and removes duplicate rows from data frames. Unlike base R’s unique(), it works naturally with tibbles and integrates into pipe-based workflows.
PySpark - Distinct Values in Column
Finding distinct values in PySpark columns is a fundamental operation in big data processing. Whether you’re profiling a new dataset, validating data quality, removing duplicates, or analyzing…
Read more →PySpark - Count Distinct Values
Counting distinct values is a fundamental operation in data analysis, whether you’re calculating unique customer counts, identifying the number of distinct products sold, or measuring unique daily…
Read more →HyperLogLog: Approximate Distinct Counting
Counting unique elements sounds trivial until you try it at scale. The naive approach—store every element in a set and count—requires memory proportional to the number of unique elements. For a…
Read more →How to Use DISTINCT ON in PostgreSQL
Think of it as ‘group by these columns, but give me the whole row, not aggregates.’
Read more →Distinct Subsequences: Counting Subsequences DP
The Distinct Subsequences problem (LeetCode 115) asks a deceptively simple question: given a source string s and a target string t, count how many distinct subsequences of s equal t.