how to write Binary table in simple way ?

Hi there,

1. How to create Binary code (like this one below) in a simple way?

     0     0     0     0
     0     0     0     1
     0     0     1     0
     0     0     1     1
     0     1     0     0
     0     1     0     1
     0     1     1     0
     0     1     1     1
     1     0     0     0
     1     0     0     1
     1     0     1     0
     1     0     1     1
     1     1     0     0
     1     1     0     1
     1     1     1     0
     1     1     1     1

2. how to print only the relevant rows like:

     0     0     1     1
     0     1     0     1
     0     1     1     0
     1     0     0     1
     1     0     1     0
     1     1     0     0

only the rows that has 2 bits that equal to 1.....

Thanks,

Henry

Answer 1

[Walter Roberson]

What happens if you use dec2bin(13) - '0' ?

A way to calculate how many values are set in a row is to sum() the row.

You should also investigate logical indexing

[Henry Buck]

I want to print only the rows that have 2 bits equal to 1. in case 13 it has 3 bits equal to one......

[Walter Roberson]

You no longer need to be able to print the complete table?

Does dec2bin(13) - '0' look like an example of a row you might want?

[Henry Buck]

no,

I want to print itlike thise one:

     0     0     1     1
     0     1     0     1
     0     1     1     0
     1     0     0     1
     1     0     1     0
     1     1     0     0

[Walter Roberson]

Does dec2bin(5)-'0' look like an example of a row you might want? Does dec2bin(6)-'0' look like an example of a row you might want?

[Henry Buck]

yes,

 dec2bin(5) = 0101
 dec2bin(6) = 0110

for table of 4 bits - it is 16 possibilities.

only those:

     0     0     1     1
     0     1     0     1
     0     1     1     0
     1     0     0     1
     1     0     1     0
     1     1     0     0

I want to print/

Thanks,

Henry

[Walter Roberson]

So if you had dec2bin(N)-'0' for some integer N, how would you test if two bits were set? See my hint about sum()

[Henry Buck]

what wrong with this one to create the binary table ?

It seems that is does not work:

n=4;           
  for i=0:(2^n-1)
      table= dec2bin(i,n)
  end

[Walter Roberson]

You are writing over "table" in each iteration of the loop.

 n=4;           
  for i=0:(2^n-1)
      table(i+1,:) = dec2bin(i,n)
  end

[Henry Buck]

Hi,

This one does not work as I want.

The resilt start like this:

table =
0000
table =
0000
0001
table =
0000
0001
0010

And end like this:

table =

0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111

16 results.... for each one, a new line fromthat tble is added.

thanks,

Henry

[Walter Roberson]

If you do not want the intermediate results printed out, put a semi-colon on the end of the assignment. You currently have

      table(i+1,:) = dec2bin(i,n)

so change that to

      table(i+1,:) = dec2bin(i,n);

Then you will only get the final result of 16 rows. When you have that, you can search it to find the rows that have 2 bits set.

[Walid KESSAL]

Here's how you can take care of that problem Mr.Henry Buck.

 n=4; tab=[];          
  for i=0:(2^n-1)
   table(i+1,:) = dec2bin(i,n);
   tab = [tab;table(i+1,:)];
  end
table = tab

the result is this

[Walter Roberson]

That code is redundant: just assigning into table() is enough without needing to build that tab variable.

Answer 2

[Pierre Bulens]

dec2bin function gives the table :

to get the rows containing 2 bits equal to 1, use the sum function and logical indexing

the sum function gives the number of 1s in each row,

the '== 2' part selects the wanted rows