I'm trying to initialize
labels =['dh';'Dh';'gj';'Gj';'ll';'Ll';'nj';'Nj';'rr';'Rr';'sh';'Sh';'th';'Th';'xh';'Xh';'zh';'Zh';'ç';'Ç';'ë';'Ë'];
But it shows me the error on title.When I try with numbers it's all perfect but not with characters.What could be the problem?
If you wish to eliminate any padding, you can also store it into a cell as follows.
labels = {'dh';'Dh';'gj';'Gj';
'll';'Ll';'nj';'Nj';
'rr';'Rr';'sh';'Sh';
'th';'Th';'xh';'Xh';
'zh';'Zh';'ç';'Ç';
'ë';'Ë'};
Then you can reference the "i"th element using labels{i} instead of labels(i,:) which is simpler. You can further run more string operations using cellfun and not interfere with any existing values that you've stored.
I agree with krisdestruction that using a cell array makes the code accessing the strings simpler and is generally more idiomatic. That is what I would also recommend unless there is a compelling reason to do something else.
For completeness, you could use the char function to add the padding automatically for you if you really want a character array:
>> char('aa','bb','c')
ans =
aa
bb
c
where the last row is 'c '. From the char documentation:
S = char(A1,...,AN) converts the arrays A1,...,AN into a single character array. After conversion to characters, the input arrays become rows in S. Each row is automatically padded with blanks as needed. An empty string becomes a row of blanks.
(Emphasis mine)
From the Mathworks documentation:
Apply the MATLAB concatenation operator, []. Separate each row with a semicolon (;). Each row must contain the same number of characters. For example, combine three strings of equal length:
You can try padding like this to make every row 2 characters:
labels = ['dh';'Dh';'gj';'Gj';
'll';'Ll';'nj';'Nj';
'rr';'Rr';'sh';'Sh';
'th';'Th';'xh';'Xh';
'zh';'Zh';'ç ';'Ç ';
'ë ';'Ë '];
Related
Based on https://www.postgresql.org/docs/13/textsearch-features.html
tsvector || tsvector
The tsvector concatenation operator returns a vector which combines the lexemes and positional information of the two vectors given as arguments. Positions and weight labels are retained during the concatenation. Positions appearing in the right-hand vector are offset by the largest position mentioned in the left-hand vector, so that the result is nearly equivalent to the result of performing to_tsvector on the concatenation of the two original document strings. (The equivalence is not exact, because any stop-words removed from the end of the left-hand argument will not affect the result, whereas they would have affected the positions of the lexemes in the right-hand argument if textual concatenation were used.)
One advantage of using concatenation in the vector form, rather than concatenating text before applying to_tsvector, is that you can use different configurations to parse different sections of the document. Also, because the setweight function marks all lexemes of the given vector the same way, it is necessary to parse the text and do setweight before concatenating if you want to label different parts of the document with different weights.
Thus this query
select 'a:1 b:2'::tsvector || 'a:1 c:2 b:3'::tsvector;
will result in 'a':1,3 'b':2,5 'c':4
Please advice is there a way to merge several tsvectors while preserving original positions (something similar to this):
select concat_with_preserving('a:1 b:2'::tsvector, 'a:1 c:2 b:3'::tsvector);
so it is equal to 'a':1 'b':2,3 'c':2, eg same positions deduplicated and different positions are just merged (w/o offset).
Thanks!
Convert then to text, then concatenate them with spaces between, then convert them back.
(a::text || ' ' || b::text)::tsvector
I am wondering what symbols are typically used to express an empty cell in a matrix. I realize that for each language and software it is different.
For MatLab: I've come across NaN or [] if the matrix is written using cell arrays like so:
>> a{2,2}=[]
a =
[1] [2]
[3] []
I think in LaTeX form, when the rows of elements are listed separated by the & symbol you would just use &(space)& to indicate an empty cell.
I'm wondering how does Mathematica express empty cells in their matrices along with other program used to do calculation on matrices.
I realize that in some cases 0's are used to express no connectivity but I'm talking about matrices (or block designs) where connectivity is not relevant and the number 0 doesn't really occur often or in some cases not at all.
I would also like to know what my best option is for empty fields if someone were to send me a covering design for example:
1,2,3,4,5
1,2,3,4,6
1,2,3,4,7
1,2,3,4,8
Where each element is separated by a delimiter (comma in this case). If their block sizes are not uniform, should I just read an empty cell as two commas together?
1,2,,4,5
Or even a comma + space
1,2, ,4,5
Also, please correct me if any of these are wrong.
The reason why I would like to know this is because I am trying to create a regex validation expression which only allows matrix forms. Which only permits matrices from all (or as many) languages and softwares.
Probably you mean the Null symbol:
Null is a symbol used to indicate the absence of an expression or a result. It is not displayed in ordinary output.
Expressions like f[e1,,e2] are interpreted to have Null between each pair of adjacent commas.
In lists:
{1, , 3} // InputForm
{1, Null, 3}
{{1,2,,4,5},
{1,2,3,4,6},
{1,2,3,4,7},
{1,2,3,4,8}}//MatrixForm
Relevant Tutorial page: "Vectors and Matrices".
I used dlmwrite to output some data in the following form:
-1.7693255974E+00,-9.7742420654E-04, 2.1528647648E-04,-1.4866241234E+00
What I really want is the following format:
-.1769325597E+00, -.9774242065E-04, .2152864764E-04, -.1486624123E+00
A space is required before each number, followed by a sign, if the number is negative, and the number format is comma delimited, in exponential form to 10 significant digits.
Just in case Matlab is not able to write to this format (-.1769325597E+00), what is it called specifically so that I can research other means of solving my problem?
Although this feels morally wrong, one can use regular expressions to move the decimal point. This is what the function
myFormat = #(x) regexprep(sprintf('%.9e', 10*x), '(\d)\.', '\.$1');
does. The input value is multiplied by 10 prior to formatting, to account for the point being moved. Example: myFormat(-pi^7) returns -.3020293228e+04.
The above works for individual numbers. The following version is also able to format arrays, providing comma separators. The second regexprep removes the trailing comma.
myArrayFormat = #(x) regexprep(regexprep(sprintf('%.9e, ', 10*x), '(\d)\.', '\.$1'), ', $', '');
Example: myArrayFormat(1000*rand(1,5)-500) returned
-.2239749230e+03, .1797026769e+03, .1550980040e+03, -.3373882648e+03, -.3810023184e+03
For individual numbers, myArrayFormat works identically to myFormat.
I am trying to generate an array of string from a long predefined array of chars as the following
if I have the following long string:
s= 'aardvaqrkaardwolfaajronabackabacusabvaftabalongeabandonabandzonedaba'
I want to create a group of random strings based on the following rules
the string should be between 4 and 12 chars should be end or start
with one of the following chars {j,q,v,f,x,g,b,d,z}
So here a solution which gives all strings which fullfill the following rules:
the starting and ending char has to be from the string:
start_end_char= 'jqvfxgbdz';
The length has to be between 4 and 8 chars long
The string has to be sequentially correct. Meaning the resulting
strings have to appear in the exact same way in the "long" string
So what am I doing?
First of all I find all the positions where the predefined starting and ending chars appear in the main string (careful I used s2 instead of s as string name).
Then I get a sorted list of those points (list_sorted)
Next thing is to get for each element a list of indices which acceptable ending chars (following rule 1 and 2 stated above). These are saved in helper which has to be a cell-datatype because of different length in the strings
last but not least I construct all those strings and save them in resulting_strings which also have to be a cell-datatype.
s2= 'aardvaqrkaardwolfaajronabackabacusabvaftabalongeabandonabandzonedaba';
start_end_char= 'jqvfxgbdz';
length_start = length(start_end_char);
%%finding all positions of possible starting/ending points
position_char= cell(1,length_start);
for k=1:length_start
position_char{k}=find(s2==start_end_char(k));
end
list_of_start_end_points=[];
%% getting an array with all starting/ending points in the given array
for k=1:length_start
list_of_start_end_points= horzcat(list_of_start_end_points,position_char{k});
end
sorted_list= sort(list_of_start_end_points);
%% getting possible combinations
helper = cell(1, length(sorted_list));
length_helper=[];
for k=1:length(sorted_list)
helper{k}=find(and(sorted_list-sorted_list(k)>=4,sorted_list-sorted_list(k)<=8));
length_helper = length_helper + length(helper);
end
resulting_strings = cell(1, length_helper);
l=1;
for k=1:length(sorted_list)
for m=1:length(helper{k})
resulting_strings{1,l} = s2(sorted_list(k):sorted_list(helper{k}(m)));
l=l+1;
end
end
This solution is using quite a few loops, while the first 2 loops are negatable (No of loops in the size of acceptable start/ending letters), the later two loops can be quite time consuming if the original string is much longer. So maybe someone will find a vectorized solution for the later loops.
I'm working on a model to use matlab as graphical representation for other model. Therefore I'd like to have a matrix that can be updated with both letters and numbers. Numbers will represent a speed while for example '-' may represent a empty section. In the matlab documentation and on internet I found a lot of interesting tips, but not what I need.
Thanks in advance!
You cannot represent data of numeric type (integers/floating points) and data of char type in a matrix. However, you can, use cells, which are similar to matrices, and can hold different data types in each cell. Here's an example.
A={[1 2 3],'hello';'world',[4,5,6]'}
A =
[1x3 double] 'hello'
'world' [3x1 double]
Here the first cell contains a row vector, the second and third cells contain strings and the fourth cell contains a column vector. Indexing into a cell is similar to that of arrays, with one minor difference: use {} to group the indices. e.g., to access the element in the second row, first column, do
A{2,1}
ans =
world
You can also access an element of an array inside a cell like
A{2,2}(2)
ans =
5
If you're wanting to store mixtures of numeric and character type data, yoda has the correct suggestion: use cell arrays.
However, based on the example you described you may have another option. If the character entries in your matrix are there for the purpose of identifying "missing data", it may make more sense to use a purely numeric matrix containing unique values like NaN or Inf to identify data points that are empty or where data is not available.
When performing operations on your matrix, you would then have to index only elements that are finite (using, for example, ISFINITE) and perform your calculations on them. There are even some functions in the Statistics Toolbox that will perform operations ignoring NaN values. This may be a cleaner way to go since you can keep your matrix as a numeric type ('single' or 'double' precision) instead of having to mess with cell arrays.