Top "Lookup" questions

Look up is related to indexes and hash tables.

Which is faster, Hash lookup or Binary search?

When given a static set of objects (static in the sense that once loaded it seldom if ever changes) into …

algorithm hash hashmap lookup binary-search
Replace values in a dataframe based on lookup table

I am having some trouble replacing values in a dataframe. I would like to replace values based on a separate …

r dataframe lookup
Lookup using INDEX and MATCH with two criteria

I am trying to achieve a basic lookup using INDEX and MATCH. My layout is: Sheet 1 NAME | SITE | DATE Sheet 2 …

excel excel-formula excel-2010 lookup excel-match
How to concatenate values in multiple cells based on a condition?

I have a need to search a row of cells, and for every cell that contains a specific value, return …

excel excel-formula lookup textjoin
Function with same name but different signature in derived class

I have a function with the same name, but with different signature in a base and derived classes. When I …

c++ function inheritance lookup c++-faq
SQL version of VLOOKUP

I am new to SQL and if you have a spare moment, I was wondering whether anybody could help me …

sql join lookup vlookup
Create sine lookup table in C++

How can I rewrite the following pseudocode in C++? real array sine_table[-1000..1000] for x from -1000 to 1000 sine_…

c++ lookup pseudocode trigonometry
MongoDB aggregation with $lookup only include (or project) some fields to return from query

In mongo, after doing an aggregation with $lookup, I would like the request to return only some fields and not …

mongodb aggregation-framework lookup
Fast computing of log2 for 64-bit integers

A great programming resource, Bit Twiddling Hacks, proposes (here) the following method to compute log2 of a 32-bit integer: #define …

c 64-bit bit-manipulation 32bit-64bit lookup
MongoDB nested lookup with 3 levels

I need to retrieve the entire single object hierarchy from the database as a JSON. Actually the proposal about any …

mongodb mongodb-query aggregation-framework lookup