I have a string containing several elements, some identical and some unique. I want my code to check every 2 following elements in my string and if they're equal, it should call a function ShuffleString, where the input variable (randomize) is the string itself, that will re-shuffle the string in a new position. Then, the script should re-check every 2 following elements in the string again until no two identical elements appear next to each other.
I have done the following:
My function file ShuffleString works fine. The input variable randomize, as stated earlier, contains the same elements as MyString but in a different order, as this was needed on an unrelated matter earlier in the script.
function [MyString] = ShuffleString(randomize)
MyString = [];
while length(randomize) > 0
S = randi(length(randomize), 1);
MyString = [MyString, randomize(S)];
randomize(S) = [];
end
The script doesn't work as intended. Right now it looks like this:
MyString = ["Cat" "Dog" "Mouse" "Mouse" "Dog" "Hamster" "Zebra" "Obama"...
"Dog" "Fish" "Salmon" "Turkey"];
randomize = MyString;
while(1)
for Z = 1:length(MyString)
if Z < length(MyString)
Q = Z+1;
end
if isequal(MyString{Z},MyString{Q})
[MyString]=ShuffleString(randomize)
continue;
end
end
end
It just seems to reshuffle the string an infinite amount of times. What's wrong with this and how can I make it work?
You are using an infinite while loop that has no way to break and hence it keeps iterating.
Here is a simpler way:
Use the third output argument of the unique function to get the elements in numeric form for easier processing. Apply diff on it to check if consecutive elements are same. If there is any occurrence of same consecutive elements, the output of diff will give at least one zero which when applied with negated all will return true to continue the loop and vice versa. At the end, use the shuffled indices/numeric representation of the strings obtained after the loop to index the first output argument of unique (which was calculated earlier). So the script will be:
MyString = ["Cat" "Dog" "Mouse" "Mouse" "Dog" "Hamster" "Zebra" "Obama"...
"Dog" "Fish" "Salmon" "Turkey"]; %Given string array
[a,~,c] = unique(MyString);%finding unique elements and their indices
while ~all(diff(c)) %looping until there are no same strings together
c = ShuffleString(c); %shuffling the unique indices
end
MyString = a(c); %using the shuffled indices to get the required string array
For the function ShuffleString, a better way would be to use randperm. Your version of function works but it keeps changing the size of the arrays MyString and randomize and hence adversely affects the performance and memory usage. Here is a simpler way:
function MyString = ShuffleString(MyString)
MyString = MyString(randperm(numel(MyString)));
end
I want to use structure in matlab but in first iteration it's run correctly and in other iteration give that message .
1x2 struct array with fields:
my code is :
for i=1:lenfd
currow=rees(i,:)
maxcn=max(currow)
if maxcn~=0
maxin=find(currow==maxcn)
ress(i).x =maxin
end
end
thank you.
That message is not a warning or error. That's just MATLAB printing the output of an operation. And it does that by default, unless you suppress it by appending a semicolon to the command:
for ii = 1:lenfd
currow = rees(ii,:); % <=== NOTE: semicolons at the end
maxcn = max(currow);
if maxcn ~= 0
ress(ii).x = find(currow==maxcn);
end
end
Note that max() may have 2 outputs, the second output being the first index into the array where the maximum occurred. If you know beforehand that any maximum will occur only once, you can skip the call to find() and use the second output of max().
I'm having trouble figuring out how to count the occurrences of a character in a string within a cell. For example, I have a file that contains information like so:
type
m
mmNs
SmNm
and I'm trying to determine how many m's are in each line. To do this, I've tried this code:
sampleddata = dataset('file','sample.txt','Delimiter','\t');
muts = sampleddata.type;
fileID = fopen('number_occur.txt','w');
for j = 1:3
mutations = muts(j)
M = length(find(mutations == 'm'));
fprintf(fileID, '%1f\n',M)
end
fclose(fileID)
However, I get an error that informs me: "Undefined operator '==' for input arguments of type 'cell'." Does anyone know how to overcome this problem?
Gonna post a result here in case you did not find a way to do it. There are loads of ways to do it, I am just going to put one of them.
Basically, you want a regex to do string matches:
a = {'type';
'm';
'mmNs';
'SmNm';
'mmmmM'} %//Load in Data,
pattern = 'm'; %//The pattern you are looking for is 'm', it could be anything really, a number of specific word or a specific pattern
lines = regexp(a, pattern, 'tokens'); %// look for this pattern in each line
result = cellfun('length',lines); %//count the size of matched patterns, so each time it matches, the size should increase by 1.
This gives the result in a matrix form:
result =
0
1
2
2
4
I'm writing some code to split up a 180x2 matlab cell array based on a string in the second column. This string is one of EP,GA,PS,SS or SA. In python I could define empty lists then use conditionals to iterate over the elements of the list and append them to the relevant lists.
The Code
EP=[];
GA=[];
PS=[];
SA=[];
SS=[];
for i=1:size(d),
if strcmp(d(i,2),'EP'),
append(EP,d(i,1))
elseif strcmp(d(i,2),'GA'),
append(GA,i)
elseif strcmp(d(i,2),'PS'),
append(PS,i)
elseif strcmp(d(i,2),'SA'),
append(SA,i)
elseif strcmp(d(i,2),'SS'),
append(SS,i)
end
end
Note that 'd' is a 180x2 cell array that I copied and pasted into matlab rather than import. The general structure of the data however is:
12.9089000000000 'EP'
13.3697000000000 'SA'
13.4335000000000 'EP'
13.5302000000000 'PS'
13.8434000000000 'EP'
14.2583000000000 'EP'
14.8221000000000 'GA'
However when attempting this tactic in matlab I get an error:
Error using append (line 38)
Wrong number of input arguments for obsolete
matrix-based syntax.
Error in Boxplot_All_results (line 12)
append(GA,i)
Could somebody tell me the correct way of doing this in matlab
First of all, please not that d is a cell array. To index the elements of a cell array, use {}. If you index using () like you did, you end up with a small cell array containing only the indexed element(s).
To append in Matlab you basically have two choices:
%concatenate the list with a scalar. Also suitable for two lists.
EP=[EP,d{i,1}] %could also be done using cat
%append to the end
EP(end+1)=d{i,1}
While this fixes the problem, I recommend to implement it on a more generic way:
names={'EP','GA','PS','SA','SS'}
s=struct()
for idx=1:numel(names)
s.(names{idx})=[d{strcmpi(d(:,2),names{idx}),1}]
end
You end up with a struct containing the data you want.
Can you show MatLab code?
How do you append those values to cell array?
You can just create one a = {}
and then append element at the size+1 index. That operation extends your cell array.
Or you can also do a trick like that: a = [a; {value}]
To append elements to a cell array, a correct syntax would be:
for i=1:size(d),
if strcmp(d(i,2),'EP'),
EP = [EP ; d(i,1) ] ; %// append(EP,d(i,1))
elseif strcmp(d(i,2),'GA'),
GA = [GA ; d(i,1) ] ; %// append(GA,i)
but there are more ways, as you can read in the documentation: Add Cells to a Cell Array
There are also more ways to build your final extracted arrays in one assignment instead of having them growing dynamically (mLint will complain about that by the way).
Get the indices of the elements which satisfy your condition then create an array with only the matching elements. For example:
iEP = cellfun( #(c) strcmp(c,'EP') , d(:,2) ) ; %// logical array of indexes where the condition is true
EP = d(iEP,1) ; %// Create "EP" in one assignment - EP is a [cell] array
If you only have numeric values to retrieve in these new variables, may be having a double array instead of a cell array will be convenient :
iGA = cellfun( #(c) strcmp(c,'GA') , d(:,2) ) ; %// logical array of indexes where the condition is true
GA = cell2mat( d(iGA,1) ) ; %// Create "GA" in one assignment - GA is a [double] array
Of course you can bypass the intermediate variable holding the indices:
PS = d( cellfun(#(c)strcmp(c,'PS'),d(:,2)),1) ; %// Create "PS" in one assignment [cell] array
SA = cell2mat(d(cellfun(#(c)strcmp(c,'SA'),d(:,2)),1)) ; %// Create "SA" in one assignment [double] array
I want to replace the value of the fields in a structure array. For example, I want to replace all 1's with 3's in the following construction.
a(1).b = 1;
a(2).b = 2;
a(3).b = 1;
a([a.b] == 1).b = 3; % This doesn't work and spits out:
% "Insufficient outputs from right hand side to satisfy comma separated
% list expansion on left hand side. Missing [] are the most likely cause."
Is there an easy syntax for this? I want to avoid ugly for loops for such simple operation.
Credits go to #Slayton, but you actually can do the same thing for assigning values too, using deal:
[a([a.b]==1).b]=deal(3)
So breakdown:
[a.b]
retrieves all b fields of the array a and puts this comma-separated-list in an array.
a([a.b]==1)
uses logical indexing to index only the elements of a that satisfy the constraint. Subsequently the full command above assigns the value 3 to all elements of the resulting comma-separated-list according to this.
You can retrieve that the value of a field for each struct in an array using cell notation.
bVals = {a.b};
bVals = cell2mat( bVals );
AFAIK, you can't do the same thing for inserting values into an array of structs. You'll have to use a loop.