Categorizing array elements based on percentage

I have an array, whose odd indices are to be divided into 4 categories based on some predefined percentage.For example, say X = [1,2.....20],odd_ind = [1 3 5...17 19], among which the first 40% are to be categorized as 1, next 30% as 2, next 20% as 3 and next 10% as 4.Could anyone guide me through this?I am a beginner and need some help with this.

Thanks in advance.

[AJAY CHANDRA DORAGARI]

first take all the odd indices out and form a matrix and then use logical opertion on the matrix

with first category say a<=0.4&a>0.3 you'll get the logical array which helps in getting elements out

second category say a<-30&a>20

and so on

i guess this will work

try this

unless you are specific i cant help you

[Walter Roberson]

Is that first 40% and so on by value, or by index?

[KK14]

index

Answer 1

[Rasul Khan]

You can have the four categories separated this way.

a = 1 : 20;
odd_ind = a(1 : 2 : end);
category1 = odd_ind( (1 : end) <= 0.4 * end );
category2 = odd_ind((1:end) > 0.4 * end & (1 : end) <= 0.7 * end );
category3 = odd_ind((1:end) > 0.7 * end & (1 : end) <= 0.9 * end );
category4 = odd_ind((1:end) > 0.9 * end );

[KK14]

Thankyou.It worked just fine for me!