statstr

The stats function computes the mean, standard deviation, and other basic statistics for numeric data and returns them in a table. The parameters may be a CImage, CMatrix, or CArray object, a 1-dimensional array, or a list of numbers. The parameters must contain numbers or strings that can be converted to numbers.

This function returns ["name"]=value pairs, whereas stats returns an indexed array, like [1]=value.

Syntax

tbl = statstr( CImage )

tbl = statstr( CImage, CRect )

tbl = statstr( CMatrix )

tbl = statstr( CArray )

tbl = statstr( table )

tbl = statstr( num1, num2, num3, ... )

The returned value tbl contains the following 8 values:

tbl["mean"] is the mean value.

tbl["median"] is the median value.

tbl["sdev"] is the standard deviation.

tbl["min"] is the minimum value.

tbl["max"] is the maximum value.

tbl["skewness"] is the statistical skewness.

tbl["kurtosis"] is the statistical kurtosis.

tbl["count"] is the number of values in the sample.

On success, tbl is returned.

On failure, nil is returned.

Example

Suppose a CImage I exists. The following script returns the mean and standard deviation of 600 pixels in the corner of the image:

tbl = statstr( I, new_rect(10,30,15,35) )	-- computes values inside the CRect
Printf("mean = %lg +/- %lg\n", tbl[mean], tbl[sdev] )	-- list the result

The next script calculates basic statistics for a series of 4 numbers:

t = statstr(1.5, 2.5, "3.5", 4.5)	-- compute stats for 4 numbers
Printf("mean = %lg +/- %lg\n", t["mean"], t["sdev"] )	--mean = 3.0 +/- 1.29099

Syntax

Example

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