How to print using fprintf to distinguisish 1.1 from 1.10 and 1.100

I am working on producing tributary pixels input file to GAMS and I need them to be numbered in a way that distinguishes 1.1 from 1.10 and 1.100. Is there a way to print a string of characters distinguishing these differences?

The way I would like my txt file to be displayed is:

1.1,0
.
.
1.10,1,1.9

a=num2str(tribarray(k).pixel,precision);  
fprintf(fid, '%s, %s, %s\n', a, num2str(size(tribarray(k).trib,2)));  %,num2str(tribarray(k).trib));
%fprintf(fid, '%s, %s, %s\n', tribarray(k).pixel, size(tribarray(k).trib,2));
for j = 1:size(tribarray(k).trib,2) 
    b=num2str(tribarray(k).trib(j));
    fprintf(fid, '%s,', b);
end

Thanks, Mariam

Answer 1

[Guillaume]

What do you mean distinguish? They're the exact same numbers:

a = 1.1;
b = 1.10;
isequal(a, b)  %return true of course.

However many zeros you wrote at the end of the number initially is immediately lost as soon as you store the number into any numeric variable. Your options are thus:

1. store your numbers as string always, never as numeric even initially:

a = '1.1'
b = '1.10'
fprintf('%s, %s', a, b)

2. store your numbers as two integers, the integral part and the fractional part:

ai = 1; af = 1;
bi = 1; bf = 10;
fprintf('%d.%d, %d.%d', ai, af, bi, bf)

----

Side note: Don't do

fprintf('%s', num2str(anumber));

but

fprintf('%d', anumber) %for integers
fprintf('%f', anumber) %for real numbers

[Mariam]

Thanks Guillaume,

Yes I understand they are the same number. It is just how I want to number my pixels. I have a grid of 102x108 pixels and the way I want to call each pixel is Row.Col so that is why I need the output file to distinguish pixel 1.1 from pixel 1.10 and similarly for 1.9 and 1.90 etc..

I used %.2f and removed the num2str but now I get all the numbers with tail zero 10.10 10.20 10.30 10.40

So my question is. Is there another way where the output would be 10.1 10.2 10.3 . . . 10.10?

So that it would display 2 digits after the decimal point only when its 10, 20 or 30?

Thanks, Mariam

[Guillaume]

Ah, that's much simpler then:

fprintf('%d.%d', row, col);

Answer 2

[Kelly Kearney]

I would just do a simple concatenation, rather than try to figure out the proper %f precision for each:

 [r,c] = meshgrid(1:108,1:102);
 lbl = arrayfun(@(x,y) sprintf('%d.%d',x,y), r, c, 'uni', 0);

Answer 3

[Mariam]

To make my question clearer I have a the structure shown below. The first column is pixel number and the second has pixels flowing into this pixel. I want to print this structure into a file such that 1.1 and 1.10 are two different pixels.

1.10000000000000 0

1.20000000000000 0

1.30000000000000 0

1.40000000000000 0

1.50000000000000 0

1.60000000000000 0 1.70000000000000 0 1.80000000000000 0 1.90000000000000 0 1.10000000000000 0

2.10000000000000 [1.10000000000000,0]

2.20000000000000 [1.20000000000000,0]

2.30000000000000 [1.30000000000000,0]

2.40000000000000 [1.40000000000000,0]

2.50000000000000 [1.50000000000000,0]

2.60000000000000 [1.60000000000000,0]

2.70000000000000 [1.70000000000000,0]

2.80000000000000 [1.80000000000000,0]

2.90000000000000 [1.90000000000000,0]

2.10000000000000 [1.10000000000000,0]

3.10000000000000 [2.10000000000000,0]

. . .

10.2000000000000 [10.1000000000000,9.20000000000000,0]

10.3000000000000 [10.2000000000000,9.30000000000000,0]

10.4000000000000 [10.3000000000000,9.40000000000000,0]

10.5000000000000 [10.4000000000000,9.50000000000000,0]

10.6000000000000 [10.5000000000000,9.60000000000000,0]

10.7000000000000 [10.6000000000000,9.70000000000000,0]

10.8000000000000 [10.7000000000000,9.80000000000000,0]

10.9000000000000 [10.8000000000000,9.90000000000000,0]

10.1000000000000 [10.9000000000000,9.10000000000000,0]

I used this code:

fid = fopen('UBNTrib_mariam1.txt', 'w');

fprintf('Neighboring Tribs List\n');

fprintf('pixel,Num tribs, Tributaries');

for k=1:size(tribarray,2)

num2str(tribarray(k).pixel),num2str(tribarray(k).trib));

fprintf(fid, '%s, %s, %s\n', num2str(tribarray(k).pixel), num2str(size(tribarray(k).trib,2)));

for j = 1:size(tribarray(k).trib,2)

fprintf(fid, '%s,', num2str(tribarray(k).trib(j)));

end

fprintf(fid, '\n');

end

fclose(fid);

% view the contents of the file type UBNTrib_mariam1.txt;

'done'

However the output is: Neighboring Tribs List pixel,Num tribs, Tributaries

1.1, 1, 0,

1.2, 1, 0,

1.3, 1, 0,

. . .

10.1, 3, 10.9,9.1,0,

so the last line for instance should be : 10.10 , 3 , 10.9, 9.10,0

Thanks a lot, Mariam

[Stephen23]

Mariam: you already accepted an answer for this question, which means that other people browsing MATLAB Answers will:

1. think that your question has been been resolved,
2. not be able to gain reputation by actually answering the question.

[Mariam]

Oh this was my first time to ask a question and didn't realize that. Thanks for letting me know

[Stephen23]

MATLAB, a new forum... it all takes time to learn :)

For your question, Guillaume gave an excellent explanation and answer:

fprintf('%d.%d', row, col)

Keep the two parts separate, and then it will be much easier to deal with.

[Star Strider]

That was also the substance of Kelly’s earlier Answer.

[Stephen23]

Yes, I just noticed Kelly's answer: they also give an excellent solution which keeps the row and column data separate.

[Guillaume]

To this I would add, that using a dot to separate the two coordinates may not be the wisest idea, since here it is not used to separate the integral and fractional parts of a number as is the norm but to separate coordinates. Any other symbol would be better (except comma which is used for the same purpose in some languages)