# inv()

Here’s how to use inv() function.

## A .inv( p )

Description:

Adjust the order of members of a sequence.

Syntax:

A.inv(p)

Note:

The function adjusts the order of members of A according to the integer sequence p, whose members are ranks of members of sequence A, and return the new A.

Parameters:

 p An integer sequence, whose members are ranks of members of A. So the number of its members is the same as that of members of A, and it is a unique n-integer sequence (n=A.len()). A A sequence or a record sequence.

Return value:

Example:

 A 1 [b,c,a,d] 2 =A1.inv([2,3,1,4]) [a,b,c,d]

Note:

p must be a unique n-integer sequence, i.e. n must be equal to A.len()

If p has duplicate members or the number of its members is not equal to that of members of A, return null.

If the maximum member value of p exceeds the maximum sequence number of A, return null

The members of tied ranks will be ignored

Related functions:

## p .inv( k )

Description:

Compute the sequence numbers of an integer’s members in another integer sequence.

Syntax:

p.inv(k)

Note:

The function returns the sequence numbers of the mumbers from 1 to k in integer sequence p. Return 0 for the numbers that do not exist in p.

Parameters:

 p An integer sequence k An integer, which is p.len() by default

Return value:

An integer sequence composed of the sequence numbers of the integers from 1 to k in integer sequence p

Example:

 A 1 =[1,3,5,7] 2 =A1.inv(4) Among the four numbers 1, 2, 3 and 4, the sequence numbers of 1 and 3 in sequence A1 are 1 and 2. 2 and 4 do not exist in sequence A1, so their sequence numbers are 0. [1,0,2,0] is returned finally.

Related functions: