# tabul

frequency of values of a matrix or vector

### Syntax

[m]=tabul(X [,order])

### Arguments

- X
vector or matrix (of real or complex numbers or strings)

- order
(optional) a character equal to "d" or "i" (default value "d")

- m
a 2 columns matrix (if

`X`

is a numerical vector or matrix) or a list with 2 members (if`X`

is a string vector or matrix).

### Description

This function computes the frequency of values of
the components of a vector or matrix `X`

of numbers or
string characters :

- if X is a numerical vector or matrix
then

`m`

is a two column matrix who contains in the first column the distinct values of`X`

and in the other column the number of occurrences of those values (m(i,2) is the number of occurrences of m(i,1)).- if X is a string vector or matrix
then

`m`

is a list whose first member is a string (column) vector composed with the distinct values of`X`

and the second member is a (column) vector whose components are the number of occurrences of those values ( m(i)(2) is the number of occurrences of the string m(i)(1) ).

The optional parameter `order`

must be "d" or "i" (by default
order="d") and gives the order (decreasing or increasing) the distinct
values of X will be sorted.

### Examples

X = [2 8 0 3 7 6 8 7 9 1 6 7 7 2 5 2 2 2 9 7] m1 = tabul(X) m2 = tabul(X, "i")

X = ["ba" "baba" "a" "A" "AA" "a" "aa" "aa" "aa" "A" "ba"] m = tabul(X,"i")

n = 50000; X = grand(n,1,"bin",70,0.5); m = tabul(X,"i"); clf() plot2d3(m(:,1), m(:,2)/n) xtitle("empirical probabilities of B(70,0.5)")

// computes the occurrences of words of the license of scilab text = read(SCI+"/COPYING",-1,1,"(A)"); // read the scilab license bigstr = strcat(text," "); // put all the lines in a big string sep = [" " "," "." ";" "*" ":" "-" """"]; // words separators words = tokens(bigstr, sep); // cut the big string into words m = tabul(words); // computes occurrences of each word [occ , p] = gsort(m(2)); // sort by decreasing frequencies results = [m(1)(p) string(occ)] // display result

### Bibliography

Wonacott, T.H. & Wonacott, R.J.; Introductory Statistics, fifth edition, J.Wiley & Sons, 1990.

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