Averages/Arithmetic mean
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You are encouraged to solve this task according to the task description, using any language you may know.
Write a program to find the mean (arithmetic average) of a numeric vector. The program should work on a zero-length vector (with an answer of 0).
J
mean=: +/ % #
That is, sum divided by the number of items. The verb also works on higher-ranked arrays. For example:
mean 3 1 4 1 5 9 3.83333 mean $0 NB. $0 is a zero-length vector 0 x=: 20 4 ?@$ 0 NB. a 20-by-4 table of random (0,1) numbers mean x 0.58243 0.402948 0.477066 0.511155
The computation can also be written as a loop. It is shown here for comparison only and is highly non-preferred compared to the version above.
mean1=: 3 : 0 z=. 0 for_i. i.#y do. z=. z+i{y end. z % #y ) mean1 3 1 4 1 5 9 3.83333 mean1 $0 0 mean1 x 0.58243 0.402948 0.477066 0.511155
Java
Assume the numbers are in a double array called "nums".
... double mean = 0; double sum = 0; for(double i : nums){ sum += i; } System.out.println("The mean is: " + ((nums.length != 0) ? (sum / nums.length) : 0)); ...