I have an excel_1 with 4 columns (A, B, C, score) with different combinations. I have another excel_2 with 3 columns (A, B, C). I would like according A, B, C and find out score. I'm trying using excel index and match function, but i still can not figure out. without coding, it really make me trouble to match it one by one...May i know how to write code in Matlab?
Example:
excel_1
99 5 35 12
99 2 32 14
97 5 13 94
...
excel_2
97 5 13
99 2 32
...
After execute the code,
Result:
excel_2
97 5 13 94
99 2 32 14
...
Thanks a lot...
A = xlsread('excel_1.xlsx');
B = xlsread('excel_2.xlsx');
[~,J] = ismember(B,A(:,1:size(B,2)),'rows');
if any(J)
result = A(J,:);
end
??? Subscript indices must either be real positive integers or logicals.
Error in ==> Untitled at 6
result = A(J,:);
Solved. can not exist impossible between B and A.
May be you can try this.
[~,J] = ismember(excel_2,excel_1(:,1:size(excel_2,2)),'rows');
if any(J)
result = excel_1(J,:);
end
Then
result =
97 5 13 94
99 2 32 14
Related
How to add the value in specific range in a matrix?
I mean if i have a matrix
Columns 1 through 7
4 4 4 4 4 4 4
48 48 48 48 48 48 48
Columns 8 through 14
4 4 4 13 13 13 13
48 48 48 57 57 57 57
Columns 15 through 20
13 13 13 13 13 13
57 57 57 57 57 57
I want to sum all 4 values ,all 13 values,all 48 values,and all 57 values,so the result should be m=[40 130 480 570]
The easiest but stupid method is like this
a=sum(1,(1:10));
b=sum(1,(11:20));
c=sum(2,(1:10));
d=sum(2,(11:20));
m=[a b c d]
If i want to write a code with for-loop or while-loop to show the result i want.how do i write the code?
Or can i use the some method to write a code without loop to show this?
Though the solution of #phnx works fine, you can also use the other outputs of the unique function in combination with accumarray as described in the docs:
[C, ~, ic] = unique(a);
a_counts = accumarray(ic,1);
m = C.*a_counts
This will avoid the warning 'hist' is not recommended...
A simple two-line solution, with A as your original matrix, would be:
[a,b]=hist(A(:),unique(A(:)))
c = a .* b'
with a containing the number of occurances, b the unique elements and c the sums.
In MATLAB (R2015a), I have two large matrices that can be simplified as:
A = [ 24 10 830; 24 15 830; 150 17 945; 231 40 1130; 231 45 1130]
(note that in A, column 3 is the time for the event cataloged in column 1) and
B = [24 13; 150 29; 231 43]
How can I match and copy the time-data from column 3 in matrix A, to a matching and filtered event column in matrix B?
For example, I want the value 24 from first column in B to be matched with value 24 from first column in A, and then copy the corresponding time-data in A's third column (for 24 it's 830, for 150 it's 945 etc.) into B. This should result into our new B with the time-data from A:
B = [24 13 830; 150 29 945; 231 43 1130]
I relatively new to MATLAB so any help is much appreciated!
First find the location of the elements in the first row of B in the first row of A using the ismember function. And then use those locations to construct the new matrix.
[~,Locb] = ismember(B(:,1),A(:,1));
Bnew = [B A(Locb,3)]
Bnew =
24 13 830
150 29 945
231 43 1130
This is a fast way that comes to my mind. There might be some singularities that needed to be checked more thoroughly.
Example, i have an array :
a = [2 3 1 2 4 5 6 4];
b = sort(a);
b = [1 2 2 3 4 4 5 6];
Now i want to combine two value of a and b :
c = [21 32 12 23 44 54 65 46]
then i do the sort of c :
d = [12 21 23 32 44 46 54 65]
and i combine again from c and d (first of c, same value of second c and first d, last d) :
e = [212 321 123 232 444 546 654 465]
then i do the sort of e :
f = [123 212 232 321 444 465 546 654]
and i combine again from e and f :
g = [2123 3212 1232 2321 4444 5465 6546 4654]
so on till the length of a that equals to 8.
Please help me.
Try this:
a = [2 3 1 2 4 5 6 4]
for m=2:8
b = sort(a)
t = round(b-10*floor(b/10))
a = 10*a+t
end
It looks to me like the algorithm just adds the last digit of each sorted list onto the corresponding number in the unsorted list. t is just the last digit in b, then 10*a+t shifts the existing digits in a and puts t at the end. Apologies if I have misunderstood the objective and this is the wrong algorithm, but it works with you example. I guess you will need to convince yourself whether the code does follow your rules.
I have an MxN matrix and I want a column vector v, using the vector s that tells me for each row in the matrix what column I will take.
Here's an example:
Matrix =
[ 4 13 93 20 42;
31 18 94 64 02;
7 44 24 91 15;
11 20 43 38 31;
21 42 72 60 99;
13 81 31 87 50;
32 22 83 24 04]
s = [4 4 5 4 4 4 3].'
And the desired output is:
v = [20 64 15 38 60 87 83].'
I thought using the expression
Matrix(:,s)
would've work but it doesn't. Is there a solution without using for loops to access the rows separately?
It's not pretty, and there might be better solutions, but you can use the function sub2ind like this:
M(sub2ind(size(M),1:numel(s),s'))
You can also do it with linear indexing, here is an example:
M=M'; s=s';
M([0:size(M,1):numel(M)-1]+s)
Quick MATLAB question.
What would be the best/most efficient way to select a certain number of elements, 'n' in windows of 'm'. In other words, I want to select the first 50 elements of a sequence, then elements 10-60, then elements 20-70 ect.
Right now, my sequence is in vector format(but this can easily be changed).
EDIT:
The sequences that I am dealing with are too long to be stored in my RAM. I need to be able to create the windows, and then call upon the window that I want to analyze/preform another command on.
Do you have enough RAM to store a 50-by-nWindow array in memory? In that case, you can generate your windows in one go, and then apply your processing on each column
%# idxMatrix has 1:50 in first col, 11:60 in second col etc
idxMatrix = bsxfun(#plus,(1:50)',0:10:length(yourVector)-50); %'#
%# reshapedData is a 50-by-numberOfWindows array
reshapedData = yourVector(idxMatrix);
%# now you can do processing on each column, e.g.
maximumOfEachWindow = max(reshapedData,[],1);
To complement Kerrek's answer: if you want to do it in a loop, you can use something like
n = 50
m = 10;
for i=1:m:length(v)
w = v(i:i+n);
% Do something with w
end
There's a slight issue with the description of your problem. You say that you want "to select the first 50 elements of a sequence, then elements 10-60..."; however, this would translate to selecting elements:
1-50
10-60
20-70
etc.
That first sequence should be 0-10 to fit the pattern which of course in MATLAB would not make sense since arrays use one-indexing. To address this, the algorithm below uses a variable called startIndex to indicate which element to start the sequence sampling from.
You could accomplish this in a vectorized way by constructing an index array. Create a vector consisting of the starting indices of each sequence. For reuse sake, I put the length of the sequence, the step size between sequence starts, and the start of the last sequence as variables. In the example you describe, the length of the sequence should be 50, the step size should be 10 and the start of the last sequence depends on the size of the input data and your needs.
>> startIndex = 10;
>> sequenceSize = 5;
>> finalSequenceStart = 20;
Create some sample data:
>> sampleData = randi(100, 1, 28)
sampleData =
Columns 1 through 18
8 53 10 82 82 73 15 66 52 98 65 81 46 44 83 9 14 18
Columns 19 through 28
40 84 81 7 40 53 42 66 63 30
Create a vector of the start indices of the sequences:
>> sequenceStart = startIndex:sequenceSize:finalSequenceStart
sequenceStart =
10 15 20
Create an array of indices to index into the data array:
>> index = cumsum(ones(sequenceSize, length(sequenceStart)))
index =
1 1 1
2 2 2
3 3 3
4 4 4
5 5 5
>> index = index + repmat(sequenceStart, sequenceSize, 1) - 1
index =
10 15 20
11 16 21
12 17 22
13 18 23
14 19 24
Finally, use this index array to reference the data array:
>> sampleData(index)
ans =
98 83 84
65 9 81
81 14 7
46 18 40
44 40 53
Use (start : step : end) indexing: v(1:1:50), v(10:1:60), etc. If the step is 1, you can omit it: v(1:50).
Consider the following vectorized code:
x = 1:100; %# an example sequence of numbers
nwind = 50; %# window size
noverlap = 40; %# number of overlapping elements
nx = length(x); %# length of sequence
ncol = fix((nx-noverlap)/(nwind-noverlap)); %# number of sliding windows
colindex = 1 + (0:(ncol-1))*(nwind-noverlap); %# starting index of each
%# indices to put sequence into columns with the proper offset
idx = bsxfun(#plus, (1:nwind)', colindex)-1; %'
%# apply the indices on the sequence
slidingWindows = x(idx)
The result (truncated for brevity):
slidingWindows =
1 11 21 31 41 51
2 12 22 32 42 52
3 13 23 33 43 53
...
48 58 68 78 88 98
49 59 69 79 89 99
50 60 70 80 90 100
In fact, the code was adapted from the now deprecated SPECGRAM function from the Signal Processing Toolbox (just do edit specgram.m to see the code).
I omitted parts that zero-pad the sequence in case the sliding windows do not evenly divide the entire sequence (for example x=1:105), but you can easily add them again if you need that functionality...