How do I use fprintf to show the entire array in one ouput statement

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Josua Mensah
Josua Mensah 2017-4-5
评论： Stephen23 2025-5-30
>>
A = [-4 2 -7 6 8; 4 -5 8 -1 0; 0 -4 3 1 10; -8 7 -10 5 -2];
[rows cols] = size(A);
Z = zeros(size(A));
for x = 1:1:rows
for y = 1:1:cols
if A(x,y) <= 4
Z(x,y) = A(x,y);
end
end
end
fprintf('%i\n',Z);
My ouput statement I am getting is
-4
4
0
-8
2
-5
-4
0
-7
0
3
-10
0
-1
1
0
0
0
0
-2
Instead of
-4 2 -7 0 0
4 -5 0 -1 0
0 -4 3 1 0
-8 0 -10 0 -2
  1 个评论
Stephen23
Stephen23 2025-5-30
Ran in:
A = [-4,2,-7,6,8; 4,-5,8,-1,0; 0,-4,3,1,10; -8,7,-10,5,-2];
Z = A;
Z(Z>4) = 0;
display(Z) % <- much simpler than FPRINTF
Z = 4×5
-4 2 -7 0 0 4 -5 0 -1 0 0 -4 3 1 0 -8 0 -10 0 -2
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采纳的回答

Jan
Jan 2017-4-5
编辑：Jan 2017-4-5
fprintf('%i %i %i %i %i\n', Z.');
or:
fprintf('%4i %4i %4i %4i %4i\n', Z.');
Note that the matrix must be transposed, because the elements are store columnwise, but the display is written in rowwise order.
By the way: It is easier without loops:
Z = zeros(size(A));
index = (A <= 4);
Z(index) = A(index);
Or:
Z = A;
Z(Z > 4) = 0;

更多回答（3 个）

Jay Stanley
Jay Stanley 2019-6-1
Tunc Durmaz,
If you do not know the dimension of your array you can get its size and replicate a template based on those dimensions
Here's a minimum working example
matrix = magic(4) % example matrix
[mrows, ncols] = size(matrix)
outputstr = ['%' num2str(mrows) 'i '] % template for the string, you put your datatype here
outputstr = repmat(outputstr, 1, ncols) % replicate it to match the number of columns
outputstr = [outputstr '\n'] % add a new line if you want
fprintf(outputstr, matrix.') % write it
For completeness sake there is another trivial solution that does not use repmat via the loop
matrix = magic(4) % example matrix
[mrows, ncols] = size(matrix)
outputstr = ['%' num2str(mrows) 'i ']
template = ['%' num2str(mrows) 'i '] % template for the string, you put your datatype here
outputstr = template
for i = 2:mcols
outputstr = [outputstr template]
end
outputstr = [outputstr '\n'] % add a new line if you want
fprintf(outputstr, matrix.') % write it
  2 个评论
Robert Laws
Robert Laws 2025-5-29
You can exploit the fact that sprintf repeats the format. Something like this can work when the data are a vector of unknown length.
ctemp=sprintf('%3i ', someintegervector);
fprintf('This is the content of the vector: %s OK', ctemp));

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Tunc Durmaz
Tunc Durmaz 2019-5-13
What if we do not know the dimension of Z? Any way to address this in fprintf?
Cheers,
Steven Lord
Steven Lord 2025-5-29
Ran in:
This wasn't an option when the question was originally asked, but if you wanted to capture the matrix in text exactly as it would be displayed in the Command Window you could use the formattedDisplayText function.
A = [-4 2 -7 6 8; 4 -5 8 -1 0; 0 -4 3 1 10; -8 7 -10 5 -2]
A = 4×5
-4 2 -7 6 8 4 -5 8 -1 0 0 -4 3 1 10 -8 7 -10 5 -2
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s = formattedDisplayText(A)
s =
" -4 2 -7 6 8 4 -5 8 -1 0 0 -4 3 1 10 -8 7 -10 5 -2 "
Let's say I wanted to cut the spacing between elements in half, replacing two spaces with one. I could manipulate the string s.
s2 = replace(s, " ", " ")
s2 =
" -4 2 -7 6 8 4 -5 8 -1 0 0 -4 3 1 10 -8 7 -10 5 -2 "
Or I could add commas after each number except the last:
s3 = regexprep(s, "(\d) ", "$1,")
s3 =
" -4, 2, -7, 6, 8 4, -5, 8, -1, 0 0, -4, 3, 1, 10 -8, 7, -10, 5, -2 "

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