how to use parameter with calculated field - tableau-api

Question

person quantity
A 2
B 3
C 4
D 5
E 8
F 10
G 15
H 20
I 55
J 30
K 21
L 4
M 6
N 10
O 25
P 22
No of people having quantity <25
No of people having quantity >25
please help for the above questions

Answer 1

First what you need to do is make a parameter of the type string:
Then you make a field that is working from the values set in the parameter. Use a case statement which has the logic "If the parameter is x, do this; if y do this"
For the "do this" part, you can use an if statement as well:
CASE [Quantity Paramter]
WHEN ">= 25 Quantity" THEN IF [Quantity] >= 25 THEN [Person] END
WHEN "< 25 Quantity" THEN IF [Quantity] < 25 THEN Person END
END
This newly created field is your new Person field and so you should drag that onto the Columns or Rows pills
Make sure to exclude the null values by using a filter on your new field. The null values in this context are the values that are not satisfying what you've chosen in the parameter. So if you've selected >=25, then a person with 2 would be a null
The below is demonstrating it working with the sample data:
Person Quantity
A 3
B 57
C 4
D 5
E 10
F 50
G 7
H 3
I 2