Averages/Arithmetic mean: Difference between revisions
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Write a program to find the mean (arithmetic average) of a numeric vector. |
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). |
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The program should work on a zero-length vector (with an answer of 0). |
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=={{header|J}}== |
=={{header|J}}== |
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mean=: +/ % # |
mean=: +/ % # |
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That is, sum divided by the number of items. |
That is, sum divided by the number of items. The verb also works on higher-ranked arrays. For example: |
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mean 3 1 4 1 5 9 |
mean 3 1 4 1 5 9 |
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0.58243 0.402948 0.477066 0.511155 |
0.58243 0.402948 0.477066 0.511155 |
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The computation can also be written as a loop. |
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. |
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is highly non-preferred compared to the version above. |
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mean1=: 3 : 0 |
mean1=: 3 : 0 |
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Revision as of 22:04, 20 January 2008
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));
...