is there any easy way to represent percentage values in Matlab
for example as in excel we can type 8% and it will represent 0.08. the % symbol is suffix to the value.
Try:
a = '%.2f%%';
%.2f%% will show the percentage to 2 decimal places and add a % at the end.
Since the percent character is part of the string formatting syntax, you have to escape it if you want to output its literal:
p = 0.08;
txt = sprintf('%.0f%%',p*100)
txt =
'8%'
For more information, read this page of the official Matlab documentation.
Related
Let's say I create some number A, of the order 10^4:
A = 81472.368639;
disp(A)
8.1472e+04
That wasn't what I wanted. Where are my decimals? There should be six decimals more. Checking the variable editor shows me this:
Again, I lost my decimals. How do I keep these for further calculations?
Scientific notation, or why you didn't lose any decimals
You didn't lose any decimals, this is just MATLAB's way of displaying large numbers. MATLAB rounds the display of numbers, both in the command window and in the variable editor, to one digit before the dot and four after that, using scientific notation. Scientific notation is the Xe+y notation, where X is some number, and y an integer. This means X times 10 to the power of y, which can be visualised as "shift the dot to the right for y places" (or to the left if y is negative).
Force MATLAB to show you all your decimals
Now that we know what MATLAB does, can we force it to show us our number? Of course, there're several options for that, the easiest is setting a longer format. The most used for displaying long numbers are format long and format longG, whose difference is apparent when we use them:
format long
A
A =
8.1472368639e+04
format longG
A
A =
81472.368639
format long displays all decimals (up to 16 total) using scientific notation, format longG tries to display numbers without scientific notation but with most available decimals, again: as many as there are or up to 16 digits, both before and after the dot, in total.
A more fancy solution is using disp(sprintf()) or fprintf if you want an exact number of decimals before the dot, after the dot, or both:
fprintf('A = %5.3f\n',A) % \n is just to force a line break
A = 81472.369
disp(sprintf('A = %5.2f\n',A))
A = 81472.37
Finally, remember the variable editor? How do we get that to show our variable completely? Simple: click on the cell containing the number:
So, in short: we didn't lose any decimals along the way, MATLAB still stores them internally, it just displays less decimals by default.
Other uses of format
format has another nice property in that you can set format compact, which gets rid of all the additional empty lines which MATLAB normally adds in the command window:
format compact
format long
A
A =
8.147236863931789e+04
format longG
A
A =
81472.3686393179
which in my opinion is very handy when you don't want to make your command window very big, but don't want to scroll a lot either.
format shortG and format longG are useful when your array has very different numbers in them:
b = 10.^(-3:3);
A.*b
ans =
1.0e+07 *
0.0000 0.0001 0.0008 0.0081 0.0815 0.8147 8.1472
format longG
A.*b
ans =
Columns 1 through 3
81.472368639 814.72368639 8147.2368639
Columns 4 through 6
81472.368639 814723.68639 8147236.8639
Column 7
81472368.639
format shortG
A.*b
ans =
81.472 814.72 8147.2 81472 8.1472e+05 8.1472e+06 8.1472e+07
i.e. they work like long and short on single numbers, but chooses the most convenient display format for each of the numbers.
There's a few more exotic options, like shortE, shortEng, hex etc, but those you can find well documented in The MathWork's own documentation on format.
I am very new to MATLAB. I am sorry if my question is basic. I am using "printmat" function to show some matrices in the command console. For example, printmat(A) and printmat(B), where A = 2.79 and B = 0.45e-7 is a scalar (for the sake of simplicity).
How do I increase the precision arbitrarily to seven decimals? For example: my output looks like 2.7943234 and B = 0.00000004563432.
How do I add a currency (say dollar) figure to the output of printmat?
How do I add a percentage figure (%) to the output of printmat?
Note: The reason I use printmat is that I can name my rows and columns. If you know a better function that can do all above, I would be glad to know.
Regards Mariam. From what I understand, you would like to display the numbers and show their full precision. I am also newbie, If I may contribute, you could convert the number data to string data (for display purposes) by using the sprintf function.
I am using the variable A=2.7943234 as example. This value will not display the full precision, instead it will display 2.7943. To show all the decimal tails, you could first convert this to string by
a = sprintf('%0.8f',A);
It will set the value a to a string '2.79432340'. The %0.8f means you want it to display 8 decimal tails. For this example,%0.7f is sufficient of course.
Another example: A=0.00000004563432, use %0.14f.
A=0.00000004563432;
a=sprintf('%0.14f $ or %%',A);
the output should be : '0.00000004563432 $ or %'.
You could analyze further in https://www.mathworks.com/help/matlab/ref/sprintf.html
You could try this first. If this does not help to reach your objective, I appreciate some inputs. Thanks.
The printmat function is very obsolete now. I think table objects are its intended successor (and functions such as array2table to convert a matrix to a table of data). Tables allow you to add row and column names and format the columns in different ways. I don't think there's a way to add $ or % to each number, but you can specify the units of each column.
In general, you can also format the display precision using format. Something like this may be what you want:
format long
I am trying to place a variable into a plot title but I cannot produce formatting of 4 decimal places. How to avoid the float format in the title?
This is the code I use
subplot(3,2,1);
hist(X,10);
str=sprintf('X N=%d,Y=%d',N,Y)
M=sum(X)/N
Mean=sprintf('Mean=%0.4d',M)
title({str,Mean})
You need to use %f as the format specifier for float values. Changing your code
Mean=sprintf('Mean=%0.4d',M)
to
Mean=sprintf('Mean=%0.4f',M)
will print M with 4 decimal places of accuracy. If you want to print M without any decimal places then you need to use %.0f
Mean=sprintf('Mean=%.0f',M)
%.0f will print a double or float value with 0 decimal places and appear as if you printed an integer with %d.
If your variable X has N elements than using the builtin MATLAB function mean() will produce the same output as sum(X) / N.
Note: You should be careful of your variable names. MATLAB includes a mean() function which you don't want to overwrite by calling a variable mean. MATLAB variable names are case-sensitive so Mean is ok but mean isn't.
You can use num2str function. For example:
mean(y)
a=num2str(ans,5)
plot(x,y)
title(['sometext ' a])
5 in num2str parameters shows maximum number of significant digits. And a is now a string.
By the way you can use mean build-in function instead your formula.
This question already has answers here:
What is the Small "e" in Scientific Notation / Double in Matlab
(2 answers)
Closed 7 years ago.
How can I write a number/Integer value to power of 10, e.g. 1000 as 10^3? I am writing code whose output is a string of very large numbers. My output in longEng format is:
4.40710646596169e+018
16.9749211806197e+186
142.220634811050e+078
508.723835280617e+204
1.15401317731033e-177
129.994388899690e+168
14.3008811642810e+153
1.25899227268954e+165
24.1450064703939e+150
627.108997290435e+144
2.03728822649372e+177
339.903986115177e-066
150.360900017430e+183
5.39003779219462e+135
183.893417489826e+198
648.544709490386e+045
19.7574461055182e+198
3.91455750674308e+102
6.41548629454028e-114
70.4943280639616e+096
19.7574461055182e+198
3.11450571506133e-009
249.857950606210e+093
4.64921904682151e+180
750.343029004712e+147
I want these results to be in a format of power of 10, so that I can easily do arithmetic operations for my next function.
you can write format shortE and see you output like this:
4.4071e+18
1.6975e+187
1.4222e+80
5.0872e+206
If you only want to print the data in scientific format, the Matlab itself can do this for you.
If you can to obtain the scientific notation form as
a * 10^b,
i.e., obtain the coefficient a and the exponent b, you can first obtain the b as:
b = floor(log10(abs(x)));
then the a as:
a = x * 10^(-b);
from my understanding you wish to take your number e.g. 4.40710646596169e+018 and split it up into:
4.40710646596169 and 018 once you have them separated you you can perform operations as you wish.
You can even join them back to look like: 4.40710646596169^018 if you so desire (although to look like that they would be strings and therefore mathematical operations on the number would be NAN).
Since e represents to the power 10 and is present in all numbers you listed this is a simple process with many solutions, here is one.
% format long is very important otherwise it will appear to you that you have
%lost precision. MATLAB hides precision from view to save screen space and to
%produce less confusing results to the viewer. (the precision is still there but
%with format long you will be able to see it.
format long
x = 4.40710646596169e+018;
%convert your number into a string, this will allow you to split the number based
%on the always present e+ 'delimiter' (not really a delimiter but looks like one')
s = num2str(x);
%use strsplit to perform the split in the required place. it will output a 1x2
%cell
D = strsplit(s, {'e+'});
%extract each cell to a separate variable. in fact D{1} can be directly used for
%the input of the next function.
D11 = D{1};
D22 = D{2};
%convert the separated strings back into numbers with double precision (keep
%maintin value accuracy)
D1 = str2double(D11)
D2 = str2double(D22)
in order to do this operation on an entire column vector it is simply a matter of using a for loop to iterate through all the numbers you have.
I have a matlab code that its output will print as an input text file for other program. But the numbers format is important in input file of my desired program it should start with 0. and then the number. For example, I want to format the output of Matlab program from the 3.00E+03 to 0.30E+04.
Can anyone between you experts kindly help me?
Many tanx
Please check the reference for fprintf. You can find it in the format specifier:
http://www.mathworks.nl/help/matlab/ref/fprintf.html
Probably the format you desire is not available in MATLAB so you can create your own!
First use log 10 to obtain the power (assuming):
Assuming a number X.
% Number to convert
X = 3867;
% Number of decimals after comma
n = 2;
% Calculation of the power to print
power = floor(log10(X))+1;
% Calculation of the decimals (correctly rounded)
decimals = round(X/10^(power-n));
% The format of fprintf. 0. is static, %d represents the printed decimals, %+0.3d represents the power. + denoting the sign, 0. denoting padding with zeros, 3 denoting the number of characters printed (if less characters in the power padded with zeros).
fprintf('0.%dE%+0.3d',decimals,power)
Kind regards,
Ernst Jan