Turn on suggestions

Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.

Showing results for

- JMP User Community
- :
- Discussions
- :
- JSL Use Lag or Dif Functions in List?

- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page

Highlighted

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Jun 7, 2013 11:27 AM
(7163 views)

Hi Folks,

I have a list ( list = {1, 3, 5, 7, 5, 9, 11, 13, 10, 14, 15, 17}; ) I want to modify so that it is monotonically increasing. That is, I want to evaluate the list so that any current value < previous value is set to previous value, else, use current value. In a JSL formula it looks like this:

If( Dif( :List, 1 ) < 0,

Lag( :List, 1 ),

:List

);

Is it possible to conduct Dif and Lag-like functions on items in a matrix? Thanks.

1 ACCEPTED SOLUTION

Accepted Solutions

Highlighted

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Matrices are fun! Loops can often be avoided if taking advantage of the matrix operations in jsl.

a = **[****1**, **3**, **5**, **7**, **5**, **9**, **11**, **13**, **10**, **14**, **15**, **17****]**;

n = N Row**(** a **)**;

pos = Loc**(** a**[****1** :: n - **1****]** > a**[****2** :: n**]** **)**;

a**[**pos + **1****]** = a**[**pos**]**;

Show**(** a **)**;

5 REPLIES 5

Highlighted
##

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Re: JSL Use Lag or Dif Functions in List?

I don't believe that there are DIF and LAG functions for a matrix, but you really don't need them. You can loop over your list/matrix and reference (i-1) or (i+1), where i is your looping index.

BTW I wouldn't use **list** as a variable, as it is a function in JSL.

Or, you can just sort your matrix:

a = **[****1**, **3**, **5**, **7**, **5**, **9**, **11**, **13**, **10**, **14**, **15**, **17]**;

b = sort ascending**(**a**)**;

**[1, 3, 5, 5, 7, 9, 10, 11, 13, 14, 15, 17]**

Highlighted
##

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Re: JSL Use Lag or Dif Functions in List?

Thanks PMroz,

I need the list to stay in the current order, just change the current value to the previous value if it is less than previous value. What I'm looking to produce is:

a = **[****1**, **3**, **5**, **7**, **7**, **9**, **11**, **13**,** 13**, **14**, **15**, **17]**;

from

a = **[****1**, **3**, **5**, **7**, **5**, **9**, **11**, **13**, **10**, **14**, **15**, **17]**;

Highlighted
##

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Re: JSL Use Lag or Dif Functions in List?

Ah OK. Then you want this:

a = **[****1**, **3**, **5**, **7**, **5**, **9**, **11**, **13**, **10**, **14**, **15**, **17]**;

for **(**i = **2**, i <= nrows**(**a**)**, i++,

if **(**a**[**i**]** < a**[**i-**1]**,

a**[**i**]** = a**[**i-**1]**;

**)**;

**)**;

**[1, 3, 5, 7, 7, 9, 11, 13, 13, 14, 15, 17]**

Highlighted

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Matrices are fun! Loops can often be avoided if taking advantage of the matrix operations in jsl.

a = **[****1**, **3**, **5**, **7**, **5**, **9**, **11**, **13**, **10**, **14**, **15**, **17****]**;

n = N Row**(** a **)**;

pos = Loc**(** a**[****1** :: n - **1****]** > a**[****2** :: n**]** **)**;

a**[**pos + **1****]** = a**[**pos**]**;

Show**(** a **)**;

Highlighted
##

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Re: JSL Use Lag or Dif Functions in List?

Thanks MS and PMroz for two interesting ways to think about and play with matrices.