In Python I am currently plotting some data and extracting the maximum values.
now i want to have a label which looks like this:
Fmax = ... and Dmax = ..., except for the max being a subscript, like "down".
The label currently looks like this:
a1.plot(z, k, label = "Kraft [Fmax: %s N], "%(round(max(k))))
Thanks for help in advance!
Unicode has some subscript letters:
u'Kraft [Fâââ: %s N], '
u'Kraft [F\u2098\u2090\u2093: %s N], ' # same value escaped for ASCII-safe source
but you would need to be using a font that supported them.
Otherwise, you would be dependent on whatever text formatting features are provided by whatever the graphics library you are using is; if none then you would have to place the max yourself manually in a smaller font at the right position.
Related
I'd like to have a function generate(n) that generates the first n lowercase characters of the alphabet appended in a string (therefore: 1<=n<=26)
For example:
generate(3) --> 'abc'
generate(5) --> 'abcde'
generate(9) --> 'abcdefghi'
I'm new to Matlab and I'd be happy if someone could show me an approach of how to write the function. For sure this will involve doing arithmetic with the ASCII-codes of the characters - but I've no idea how to do this and which types that Matlab provides to do this.
I would rely on ASCII codes for this. You can convert an integer to a character using char.
So for example if we want an "e", we could look up the ASCII code for "e" (101) and write:
char(101)
'e'
This also works for arrays:
char([101, 102])
'ef'
The nice thing in your case is that in ASCII, the lowercase letters are all the numbers between 97 ("a") and 122 ("z"). Thus the following code works by taking ASCII "a" (97) and creating an array of length n starting at 97. These numbers are then converted using char to strings. As an added bonus, the version below ensures that the array can only go to 122 (ASCII for "z").
function output = generate(n)
output = char(97:min(96 + n, 122));
end
Note: For the upper limit we use 96 + n because if n were 1, then we want 97:97 rather than 97:98 as the second would return "ab". This could be written as 97:(97 + n - 1) but the way I've written it, I've simply pulled the "-1" into the constant.
You could also make this a simple anonymous function.
generate = #(n)char(97:min(96 + n, 122));
generate(3)
'abc'
To write the most portable and robust code, I would probably not want those hard-coded ASCII codes, so I would use something like the following:
output = 'a':char(min('a' + n - 1, 'z'));
...or, you can just generate the entire alphabet and take the part you want:
function str = generate(n)
alphabet = 'a':'z';
str = alphabet(1:n);
end
Note that this will fail with an index out of bounds error for n > 26, so you might want to check for that.
You can use the char built-in function which converts an interger value (or array) into a character array.
EDIT
Bug fixed (ref. Suever's comment)
function [str]=generate(n)
a=97;
% str=char(a:a+n)
str=char(a:a+n-1)
Hope this helps.
Qapla'
I want to use fscanf for reading a text file containing 4 rows with an unknown number of columns. The newline is represented by two consecutive spaces.
It was suggested that I pass : as the sizeA parameter but it doesn't work.
How can I read in my data?
update: The file format is
String1 String2 String3
10 20 30
a b c
1 2 3
I have to fill 4 arrays, one for each row.
See if this will work for your application.
fid1=fopen('test.txt');
i=1;
check=0;
while check~=1
str=fscanf(fid1,'%s',1);
if strcmp(str,'')~=1;
string(i)={str};
end
i=i+1;
check=strcmp(str,'');
end
fclose(fid1);
X=reshape(string,[],4);
ar1=X(:,1)
ar2=X(:,2)
ar3=X(:,3)
ar4=X(:,4)
Once you have 'ar1','ar2','ar3','ar4' you can parse them however you want.
I have found a solution, i don't know if it is the only one but it works fine:
A=fscanf(fid,'%[^\n] *\n')
B=sscanf(A,'%c ')
Z=fscanf(fid,'%[^\n] *\n')
C=sscanf(Z,'%d')
....
You could use
rawText = getl(fid);
lines = regexp(thisLine,' ','split);
tokens = {};
for ix = 1:numel(lines)
tokens{end+1} = regexp(lines{ix},' ','split'};
end
This will give you a cell array of strings having the row and column shape or your original data.
To read an arbitrary line of text then break it up according the the formating information you have available. My example uses a single space character.
This uses regular expressions to define the separator. Regular expressions powerful but too complex to describe here. See the MATLAB help for regexp and regular expressions.
I have a string and I need two characters to be returned.
I tried with strsplit but the delimiter must be a string and I don't have any delimiters in my string. Instead, I always want to get the second number in my string. The number is always 2 digits.
Example: 001a02.jpg I use the fileparts function to delete the extension of the image (jpg), so I get this string: 001a02
The expected return value is 02
Another example: 001A43a . Return values: 43
Another one: 002A12. Return values: 12
All the filenames are in a matrix 1002x1. Maybe I can use textscan but in the second example, it gives "43a" as a result.
(Just so this question doesn't remain unanswered, here's a possible approach: )
One way to go about this uses splitting with regular expressions (MATLAB's strsplit which you mentioned):
str = '001a02.jpg';
C = strsplit(str,'[a-zA-Z.]','DelimiterType','RegularExpression');
Results in:
C =
'001' '02' ''
In older versions of MATLAB, before strsplit was introduced, similar functionality was achieved using regexp(...,'split').
If you want to learn more about regular expressions (abbreviated as "regex" or "regexp"), there are many online resources (JGI..)
In your case, if you only need to take the 5th and 6th characters from the string you could use:
D = str(5:6);
... and if you want to convert those into numbers you could use:
E = str2double(str(5:6));
If your number is always at a certain position in the string, you can simply index this position.
In the examples you gave, the number is always the 5th and 6th characters in the string.
filename = '002A12';
num = str2num(filename(5:6));
Otherwise, if the formating is more complex, you may want to use a regular expression. There is a similar question matlab - extracting numbers from (odd) string. Modifying the code found there you can do the following
all_num = regexp(filename, '\d+', 'match'); %Find all numbers in the filename
num = str2num(all_num{2}) %Convert second number from str
Is it possibe to create an array of strings in MATLAB within a for loop?
For example,
for i=1:10
Names(i)='Sample Text';
end
I don't seem to be able to do it this way.
You need to use cell-arrays:
names = cell(10,1);
for i=1:10
names{i} = ['Sample Text ' num2str(i)];
end
You can create a character array that does this via a loop:
>> for i=1:10
Names(i,:)='Sample Text';
end
>> Names
Names =
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
However, this would be better implemented using REPMAT:
>> Names = repmat('Sample Text', 10, 1)
Names =
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Another option:
names = repmat({'Sample Text'}, 10, 1)
New features have been added to MATLAB recently:
String arrays were introduced in R2016b (as Budo and gnovice already mentioned):
String arrays store pieces of text and provide a set of functions for
working with text as data. You can index into, reshape, and
concatenate strings arrays just as you can with arrays of any other
type.
In addition, starting in R2017a, you can create a string using double quotes "".
Therefore if your MATLAB version is >= R2017a, the following will do:
for i = 1:3
Names(i) = "Sample Text";
end
Check the output:
>> Names
Names =
1Ă3 string array
"Sample Text" "Sample Text" "Sample Text"
No need to deal with cell arrays anymore.
Another solution to this old question is the new container string array, introduced in Matlab 2016b. From what I read in the official Matlab docs, this container resembles a cell-array and most of the array-related functions should work out of the box. For your case, new solution would be:
a=repmat('Some text', 10, 1);
This solution resembles a Rich C's solution applied to string array.
As already mentioned by Amro, the most concise way to do this is using cell arrays. However, Budo touched on the new string class introduced in version R2016b of MATLAB. Using this new object, you can very easily create an array of strings in a loop as follows:
for i = 1:10
Names(i) = string('Sample Text');
end
one of the simplest ways to create a string matrix is as follow :
x = [ {'first string'} {'Second parameter} {'Third text'} {'Fourth component'} ]
A=rand(10)
B=find(A>98)
How do you have text saying "There were 2 elements found" where the 2 is general i.e. it isn't text, so that if I changed B=find(A>90) it would automatically no longer be 2.
some_number = 2;
text_to_display = sprintf('There were %d elements found',some_number);
disp(text_to_display);
Also, if you wanted to count the number of elements greater than 98 in A, you should one of the following:
numel(find(A>98));
Or
sum(A>98);
sprintf is a very elegant way to display such data and it's quite easy for a person with a C/C++ background to start using it. If you're not comfortable with the format-specifier syntax (check out the link) then you can use:
text_to_display = ['There were ' num2str(some_number) ' elements found'];
But I would recommend sprintf :)