Tools to select numbers randomly, make random draws of numbers according to several criteria and let randomness/chance decide.
Random Numbers - dCode
Tag(s) : Fun/Miscellaneous, Algorithm, Combinatorics
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Random Numbers
Random Numbers Selection
Answers to Questions (FAQ)
What is a random number? (Definition)
A random number is a number selected at random from an interval. The randomly selected number is usually either an integer or a decimal number.
Most often the number is calculated by computer using pseudo-randomness functions like rand() or random().
How to make a random number selection?
Indicate the type of numbers to draw:
— choice according to an interval: select numbers between $ a $ and $ b $
Example: Draw $ N $ digits between $ 1 $ and $ 100 $
— choice according to a size: select numbers with a certain number of digits
— choice according to a list: select numbers from a given list
Example: A phone number corresponds to N digits from 0 to 9
What is a random number sample without replacement?
A draw without replacement specifies that a picked number can not be picked a second time.
Example: Draws of $ 3 $ numbers between $ 1 $ and $ 5 $ could be $ 4,2,3 $ or $ 1,5,2 $ but never $ 1,2,2 $ (the $ 2 $ having been picked a first time, it is not put back into play)
During a draw without replacement, it is not possible to pick more than $ N $ numbers in a range of size $ N $
Example: A selection of $ 100 $ numbers between $ 1 $ and $ 20 $ is impossible without replacement
What is a random number sample with replacement?
A draw with replacement specifies that a picked number may be picked one or more times.
Example: Draws of $ 3 $ numbers between $ 1 $ and $ 5 $ could be $ 4,2,3 $ or $ 1,5,2 $ but also $ 1,2,2 $ (the $ 2 $ having been picked a first time, it is put back into play and can stand out)
During a draw with replacement, it is possible to pick more than $ N $ numbers in a range of size $ N $
Example: A selection of $ 100 $ numbers between $ 1 $ and $ 20 $ is possible with replacement
How to pick only even numbers?
Option 1: list the even numbers (if there are not too many) and draw from this list.
Option 2: Multiply the numbers obtained by 2, they will all be even.
Source code
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