topic Re: Talend calculation in Talend Studio

Talend calculation

krengan21 — Tue, 28 Nov 2017 12:20:00 GMT

How to get the actual value from the cummulative value in talend ? for example On a paricular a car runs for 1000 kms next day the car will start from 1001 kms ,So what i need is how to calculate the total kms covered on a particular day

1000kms on 27-10-2017 2000kms on 28-10-2017

so the total kms covered on 28-10-2017 is 1000kms how to do that in talend for which i need to update around 1 lakh history records using the above method and this needs to be done in mongodb

Re: Talend calculation

Anonymous — Tue, 28 Nov 2017 12:35:05 GMT

Assuming your data looks similar to this.....

Day Total Miles
1 100
2 150

3 175

4 230
5 301

.....and you want to get the values.....

1 = 100
2= 50
3 = 25
4 = 55

5 = 71

....you can do it with a tMap. I have done this to demonstrate. The screenshot of the tMap is below....

The tMap variables (the box in the middle) must be set up exactly as above. The expressions are....

todaysDistance

Var.lastDistance!=null ? row1.miles - Var.lastDistance : row1.miles

lastDistance

row1.miles

The trick here is that the tMap variables keep their values between rows and are processed in order.

Your dates must come in in order for this.

Re: Talend calculation

krengan21 — Tue, 28 Nov 2017 12:41:33 GMT

Hi ,
i am not getting the solution you gave .Can you please elaborate on this whether i need to use tmemorizerow for memorising the previous value or something like that ?

Re: Talend calculation

krengan21 — Tue, 28 Nov 2017 12:58:45 GMT

I need to calculate based on the customer id how to include that condition in tmap

Re: Talend calculation

Anonymous — Tue, 28 Nov 2017 13:09:57 GMT

You do not need to use tMemorizeRow. This configuration will work without that.

To do this via CustomerId, you will need to sort your data by CustomerID and date first (tSortRow), then have some logic to decide when your CustomerId switches. You can do this using the tMap variables as well. However this is a different question and I have thrown away my example.

Accept this as the solution (if it shows the distance between days, forgetting the CustomerID) and raise the CustomerID changing as a different question. There should only be one question per post.

Re: Talend calculation

krengan21 — Tue, 28 Nov 2017 13:19:20 GMT

The operator != is undefined for the argument type(s) int, null
There may be some other errors caused by JVM compatibility. Make sure your JVM setup is similar to the studio. Is the error i am getting

Re: Talend calculation

krengan21 — Tue, 28 Nov 2017 13:21:14 GMT

Re: Talend calculation

krengan21 — Tue, 28 Nov 2017 14:03:13 GMT

i am getting the cummulative value not the subtracted one

Re: Talend calculation

Anonymous — Tue, 28 Nov 2017 14:04:26 GMT

If you are using Talend 6 you should be using java 8.

int is a primitive type. This means that your tick boxes next to your variable config are not ticked. The "Nullable" tick box means they become Integer objects instead of int types.

Re: Talend calculation

Anonymous — Tue, 28 Nov 2017 14:05:46 GMT

Not if you are following the example I gave you. Can you take a screenshot of what you have?

Re: Talend calculation

krengan21 — Tue, 28 Nov 2017 14:08:42 GMT

11569|1
27752|1
27797|1

this is the output i am getting instead of the expected one.

The expression used are as follows

Var.lastDistance!=null ? row1.distance - Var.lastDistance : row1.distance for today distance

row1.distance for last distance

Please tell me what is the issue

Re: Talend calculation

Anonymous — Tue, 28 Nov 2017 14:20:31 GMT

I need a screenshot of your tMap config