# present decimal values in a pie graph

조회 수: 36(최근 30일)
Nitai 3 May 2019
편집: dpb 3 May 2019
Hello, I'm struggling in a specific action in a pie graph. After I input a vector of numbers, if the sum of the numbers is bigger than 100, than the program should do the following action in a for loop.
afterwards a pie graph should be created and the numbers should be presented in their decimal value. my code works fine and creates the graph besides the decimal part. I would love to get a hand in here how to turn my values into their decimal values (I know this code won't do it, I'm not familiar with any command that would do that).
else sum(num) > 100
for i = 1 ; length(num) %for loop that takes every value, divides it by the sum of the vector and multiply by 100%
num(i) = ((num(i)/sum(num))*100);
end
pie(num);

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### 채택된 답변

dpb 3 May 2019
편집: dpb 3 May 2019
...
for i = 1 ; length(num) % ";" should be ":"
num(i) = ((num(i)/sum(num))*100);
end
Use Matlab array syntax instead of loops...
num=100*num/sum(num); % Matlab is "MATrix LABoratory", use vectorized operations
pie(num,cellstr(num2str(num(:),'%05.2f%'))) % write percentages as labels
NB: the (:) on the num array to ensure is column vector in argument to num2str to ensure generates a columnar list of char strings; a row vector gets turned into one long string instead, not at all what you want.
"Salt to suit" the precision for the format string...
Fixed missing cellstr() cast and mistyped format string (had 5f.2 rather than 5.2f)

#### 댓글 수: 2

Nitai 3 May 2019
hey DB, thx for your help. when i try to write this:
num=100*num/sum(num); % Matlab is "MATrix LABoratory", use vectorized operations
pie(num,num2str(num(:),'%05f.2')) % write percentages as labels
it won't work and displays the following error:
Error using pie (line 71)
X and EXPLODE must be the same length.
and i didnt completly understand your note at the end of your msg.
any thougths?
dpb 3 May 2019
Was off the doc; hadn't tried it...needs a cellstr() array, not a cell array of char() it appears...
pie(num,num2str(num(:),'%05.2f%')) % write percentages as labels
Actually, I see that if you're happy with just percentages as the integer values that pie does that automatically; you don't need to write the text at all...if you want more precision, looks like need to supply.
pie(num) % shows percentages as integers by default
As far as the last comment, see difference between
>> x % some sample percentage values
x =
33.33
35.29
3.92
15.69
11.76
>> cellstr(num2str(x,'%05.2f')) % x is column vector, get column of cellstr()
ans =
5×1 cell array
{'33.33'}
{'35.29'}
{'03.92'}
{'15.69'}
{'11.76'}
>> cellstr(num2str(x.','%05.2f')) % if x is row vector (.' does that to column)
ans =
1×1 cell array
{'33.3335.2903.9215.6911.76'}
>>
the last ends up with one long string of the numbers in internal storage order of the string representation of the values of x -- not at all what you want/need...

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