Validating Postal Codes

Problem Statement The task is to write a function that validates whether a given postal code string meets certain conditions such as being a six-digit number with specific digits at specific positions and having a certain sum of digits. Link:¬†HackerRank Complexity: Hard Solution: The solution to this problem involves the use of regular expressions. We define …

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Understanding Dense Rank

What is DENSE_RANK? DENSE RANK is a window function in SQL that is used to assign a rank to each row within a result set. The rank assigned to each row is based on the values in one or more columns specified in the ORDER BY clause. The DENSE RANK function is similar to the …

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Building Interactive Visualisations Using Plotly

Plotly is a powerful data visualization library that allows you to create interactive charts and graphs. With Plotly, you can create everything from simple line charts to complex 3D visualisations with ease. In this article, we’ll cover the basics of creating interactive visualizations using Plotly, and we’ll provide examples to help you get started. Getting …

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Data Analysis and Visualization in Python

Data analysis and data visualisation are two closely related activities in the field of data science. Getting insights from data using statistical and computational methods is part of data analysis. This process may involve cleaning and transforming the data, and then performing various statistical tests and modeling techniques to extract insights. Once the data analysis …

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LEAD and LAG Functions

LAG and LEAD are SQL analytic functions that allow you to access data from a previous or subsequent row in a query result set. LAG provides access to a previous row, while LEAD provides access to the following row. For example, imagine you have a table of sales data with columns for date, product, and …

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Human Traffic of Stadium (SQL #601)

This task requires to find Human Traffic of Stadium. We need to write a SQL query to extract records with three or more consecutive rows that have an ID and people count greater than or equal to 100. The resulting table should be sorted in ascending order by visit_date. Problem Statement Link: LeetCode Complexity: Hard Table: Stadium +—————+———+ …

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