Table Functions

Table Functions

These functions work with general multi-dimensional tables that contain sub-tables within the primary table. They also support tables with or without keys and with any type of values. Their names have an extra "n" appended to signify that they support table with higher dimensions. Most are generalizations of the Array Functions that support 1-dimensional arrays (indexed tables). However, none of these table functions support either class objects, like CImage, or lists of numbers. Most functions perform some type of mathematical processing by selecting only the numeric values in the table.

Several of the table functions return the processed table which can become the input of another function. For example, the following table equation is possible: x = meann( muln( addn( tbl, 20.5), 0.42 ) )). This adds 20.5 to all numeric value in table tbl, then multiples that by 0.42, then calculates the mean value x.

These functions create the possibility of mixing the numeric data of a 1-dimensional indexed array with non-numerc data that describes the data in the array. This works because lua tables are a general structuring element that can contain nearly any type of data. These functions can then be used to operate on the purely numeric data while leaving the keyed data intact. For example, consider the following table which contains two keys, name and cval:

t = { 6, -2, 15, name="my identifier", cval="5.4", 5.04 }

Applying the table function sumn(t) returns the sum of numeric elements, which is 24.04. Similarly, t2 = addn(t,4.5) gives the following result:

t2 = { 10.5, 2.5, 19.5, name="my identifier", cval="5.4", 9.54 }

Table Functions
addn	Adds a number to the numeric values in a general table.
divn	Divides a number into the numeric values in a general table.
flatten	Flattens the numeric values of a general table into a 1-dimensional array
flattenn	Flattens all values of a general table into a 1-dimensional array
harmeann	Calculates the harmonic mean of the numeric values in a general table.
harmeansdevn	Calculates the harmonic mean and standard deviation of the numeric values in a general table.
ismultidim	Returns true of the specified table has more than one dimension (i.e., contains at least on sub-table).
list	Lists the contents of a table.
maxn	Returns the maximum value in a general table.
meann	Returns the mean for the numeric values in a general table
meansdevn	Returns the mean and standard deviation for the numeric values in a general table
mediann	Returns the median for the numeric values in a general table.
mediansdevn	Returns the median and standard deviation for the numeric values in a general table.
minn	Returns the minimum value of the numeric values in a general table.
muln	Multiples the numeric values in a general table by a specified number.
normn	Normalizes the numeric values in a general table so their sum is 1.0.
rankn	Returns the specified rank value for numeric values in a general table.
sdevn	Returns the standard deviation of numeric values in a general table.
sdevxn	Returns the standard deviation about a specified value for a general table.
subn	Subtracts a number from the numeric values of a general table.
sumn	Returns the sum of numeric values in a general table.
tcountn	Returns the count of numeric elements in a general table.
xdivn	Divided each member of a general table into a specified number. This is often called "reverse division."

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