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SQL Interview Success: Unlocking the Top 5 Frequently Asked Queries

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 Here are the five top commonly asked SQL queries in the interviews. These you can expect in Data Analyst, or, Data Engineer interviews. Top SQL Queries for Interviews 01. Joins The commonly asked question pertains to providing two tables, determining the number of rows that will return on various join types, and the resultant. Table1 -------- id ---- 1 1 2 3 Table2 -------- id ---- 1 3 1 NULL Output ------- Inner join --------------- 5 rows will return The result will be: =============== 1  1 1   1 1   1 1    1 3    3 02. Substring and Concat Here, we need to write an SQL query to make the upper case of the first letter and the small case of the remaining letter. Table1 ------ ename ===== raJu venKat kRIshna Solution: ========== SELECT CONCAT(UPPER(SUBSTRING(name, 1, 1)), LOWER(SUBSTRING(name, 2))) AS capitalized_name FROM Table1; 03. Case statement SQL Query ========= SELECT Code1, Code2,      CASE         WHEN Code1 = 'A' AND Code2 = 'AA' THEN "A" | "A

Python Set comprehension - How to Use it Read now

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In python, Set does not allow duplicates, and  you can't modify an existing set with a comprehension. But using the Set comprehension you can create a new Set. Set Comprehension  In addition, the comprehension must result in a valid set.  Likewise Dictionary, a set does not allow entries of the same value. If you try to add values to the set that are already there, it will replace the old one with the new one. Explained syntax Set comprehensions using the {} syntax only exist in Python 3. Before that, you'll have to use the set() function to create and work with sets. You might guess, therefore, that one of the best uses of a set is to eliminate duplicates. In fact, this is one of the most basic forms of set comprehension. Given a list, we can duplicate it as a list with a simple list comprehension like this: Details of logic if we change the list comprehension to a set comprehension, we get the same result, but as a set. That means without duplicates. list_copy = [x for x in o