I have a cell array called BodyData in MATLAB that has around 139 columns and 3500 odd rows of skeletal tracking data.
I need to extract all rows between two string values (these are timestamps when an event happened) that I have
e.g.
BodyData{}=
Column 1 2 3
'10:15:15.332' 'BASE05' ...
...
'10:17:33:230' 'BASE05' ...
The two timestamps should match a value in the array but might also be within a few ms of those in the array e.g.
TimeStamp1 = '10:15:15.560'
TimeStamp2 = '10:17:33.233'
I have several questions!
How can I return an array for all the data between the two string values plus or minus a small threshold of say .100ms?
Also can I also add another condition to say that all str values in column2 must also be the same, otherwise ignore? For example, only return the timestamps between A and B only if 'BASE02'
Many thanks,
The best approach to the first part of your problem is probably to change from strings to numeric date values. In Matlab this can be done quite painlessly with datenum.
For the second part you can just use logical indexing... this is were you put a condition (i.e. that second columns is BASE02) within the indexing expression.
A self-contained example:
% some example data:
BodyData = {'10:15:15.332', 'BASE05', 'foo';...
'10:15:16.332', 'BASE02', 'bar';...
'10:15:17.332', 'BASE05', 'foo';...
'10:15:18.332', 'BASE02', 'foo';...
'10:15:19.332', 'BASE05', 'bar'};
% create column vector of numeric times, and define start/end times
dateValues = datenum(BodyData(:, 1), 'HH:MM:SS.FFF');
startTime = datenum('10:15:16.100', 'HH:MM:SS.FFF');
endTime = datenum('10:15:18.500', 'HH:MM:SS.FFF');
% select data in range, and where second column is 'BASE02'
BodyData(dateValues > startTime & dateValues < endTime & strcmp(BodyData(:, 2), 'BASE02'), :)
Returns:
ans =
'10:15:16.332' 'BASE02' 'bar'
'10:15:18.332' 'BASE02' 'foo'
References: datenum manual page, matlab help page on logical indexing.
Related
What is wrong with this expression? =CountRows(ReportItems!Textbox58.Value = "Intervene")
I want to count each row which says Intervene.
As Larnu has commented, you cannot use CountRows against the ReportItems collection.
Probably what you need to do is
Look at the expression in Textbox58 and see where it gets it's data from. In this exmaple let's say it comes from Fields!myFieldName.Value.
Now we need to count the rows where Fields!myFieldName.Value = "Intervene" but rather than using count, we can convert these matches to return 1 or 0 where the field is not "Intervene"
So the expression would look something like this
=SUM(IIF(Fields!myFieldName.Value = "Intervene", 1, 0))
This will sum the rows withing the current scope, so if this is contained in a row group for example, then it will only sum those rows in that row group.
If you need to count based on a a different scope (e.g. the entire dataset) then you can specify that in the SUM() function like this
=SUM(IIF(Fields!myFieldName.Value = "Intervene", 1, 0), "DataSet1")
Here we are summing across the entire dataset where the dataset name is DataSet1
Update based on OP comment
As your expression is
=SUM(IIF(Fields!Actual_Duration.Value >= 10, "Intervene", "No Intervention Needed"))
What we actually need to count is instances where Actual_Duration is >= 10.
So the final expression should be
=SUM(IIF(Fields!Actual_Duration.Value >= 10, 1, 0))
I have an array that contains multiple dates in the format yyyymmdd, stored as a 50x1 double. I am trying to pull out the year,month, and day so I can use datenum to assign each date a serial number.
Indexing an individual date, converting the using str2num, then indexing and pulling the appropriate values works fine, but when I try to loop through the list of dates it doesn't work- only variations of the number 2 are returned.
dates = [20180910; 20180920; 20181012; 20181027; 20181103; 20181130; 20181225];
% version1
datesnums=num2str(dates); % dates is a list of dates stored as
integers
for i=1:length(datesnums)
pullyy=str2num(datesnums(1:4));
pullmm=str2num(datesnums(5:6));
pulldd=str2num(datesnums(7:8));
end
As well as
%version2
datesnums=num2str(dates,'%d')
for i = 1:length(datesnums)
dd=datenum(str2num(datesnums(i(1:4))),str2num(datesnums(i(5:6))),
str2num(datesnums(i(7:8))));
end
I'm trying to generate a new array that is just the serial numbers of the input dates. In the examples shown, I am only getting single integer values, which I know is because the loop is incorrect and I get errors that say "Index exceeds the number of array elements (1)." for version 1. When I've gotten it to successfully loop through everything, the outputs are just '2222','22,'22' for every single date which is incorrect. What am I doing wrong? Do I need to incorporate a cell array?
To get all the years, month, and days in a loop:
datesnums=num2str(dates);
for i=1:size(datesnums, 1)
pullyy(i) = str2num(datesnums(i,1:4));
pullmm(i) = str2num(datesnums(i,5:6));
pulldd(i) = str2num(datesnums(i,7:8));
end
Actually, you can do this without a loop:
pullyy = str2num(datesnums(:,1:4));
pullmm = str2num(datesnums(:,5:6));
pulldd = str2num(datesnums(:,7:8));
Explanation:
If for example the dates vector is a [6x1] array:
dates =[...
20190901
20170124
20191215
20130609
20141104
20190328];
Than datesnums=num2str(dates); creates a char matrix of size [6x8] where each row corresponds to one element in dates:
datesnums =
6×8 char array
'20190901'
'20170124'
'20191215'
'20160609'
'20191104'
'20190328'
So in the loop you need to refer to the row index for each date and and the column indices to extract the years, month, and days.
The easiest solution I can think of is:
SN = datenum(num2str(dates),'yyyymmdd')
You only have to specify the date format which is 'yyyymmdd'
I am using matlab to prepare my dataset in order to run it in certain data mining models and I am facing an issue with linking the data between two of my tables.
So, I have two tables, A and B, which contain sequential recordings of certain values in a certain timestamps and I want to create a third table, C, in which I will add columns of both A and B in the same rows according to some conditions.
Tables A and B don't have the same amount of rows (A has more measurements) but they both have two columns:
1st column: time of the recording (hh:mm:ss) and
2nd column: recorded value in that time
Columns of A and B are going to be added in table C when all the following conditions stand:
The time difference between A and B is more than 3 sec but less than 5 sec
The recorded value of A is the 40% - 50% of the recorded value of B.
Any help would be greatly appreciated.
For the first condition you need something like [row,col,val]=find((A(:,1)-B(:,1))>2sec && (A(:,1)-B(:,1))<5sec) where you do need to use datenum or equivalent to transform your timestamps. For the second condition this works the same, use [row,col,val]=find(A(:,2)>0.4*B(:,2) && A(:,2)<0.5*B(:,2)
datenum allows you to transform your arrays, so do that first:
A(:,1) = datenum(A(:,1));
B(:,1) = datenum(B(:,1));
you might need to check the documentation on datenum, regarding the format your string is in.
time1 = [datenum([0 0 0 0 0 3]) datenum([0 0 0 0 0 3])];
creates the datenums for 3 and 5 seconds. All combined:
A(:,1) = datenum(A(:,1));
B(:,1) = datenum(B(:,1));
time1 = [datenum([0 0 0 0 0 3]) datenum([0 0 0 0 0 3])];
[row1,col1,val1]=find((A(:,1)-B(:,1))>time1(1)&& (A(:,1)-B(:,1))<time1(2));
[row2,col2,val2]=find(A(:,2)>0.4*B(:,2) && A(:,2)<0.5*B(:,2);
The variables of row and col you might not need when you want only the values though. val1 contains the values of condition 1, val2 of condition 2. If you want both conditions to be valid at the same time, use both in the find command:
[row3,col3,val3]=find((A(:,1)-B(:,1))>time1(1)&& ...
(A(:,1)-B(:,1))<time1(2) && A(:,2)>0.4*B(:,2)...
&& A(:,2)<0.5*B(:,2);
The actual adding of your two arrays based on the conditions:
C = A(row3,2)+B(row3,2);
Thank you for your response and help! However for the time I followed a different approach by converting hh:mm:ss to seconds that will make the comparison easier later on:
dv1 = datevec(A, 'dd.mm.yyyy HH:MM:SS.FFF ');
secs = [3600,60,1];
dv1(:,6) = floor(dv1(:,6));
timestamp = dv1(:,4:6)*secs.';
Now I am working on combining both time and weight conditions in a piece of code that will run. Should I use an if condition inside a for loop or is a for loop not necessary?
I have a date cell array which is read from a csv file. The format is below:
date =
'2008.12.01'
'2008.12.02'
'2008.12.03'
'2008.12.04'
'2008.12.05'
... ...
And I want to:
turn the cell array to a string array,
use the strread() to read its "yyyy","mm" and "dd" value into 3 double array [year,mm,dd],
use the datenummx() to turn [year,mm,dd] into date seriel num.
After i use
date = char(date);
the date array become like this:
date =
2008.12.01
2008.12.02
2008.12.03
2008.12.04
2008.12.05
... ...
which I think the result is what i want...
But after I use the strread(), it gives me odd result.
[year,month,day]=strread(date,'%d%d%d','delimiter','.');
year =
-1
0
0
0
0
... ...
BUT if I use the code below, the strread() can give me the right answer:
s = sprintf('2008.12.01')
s =
2008.12.01
[year,month,day]=strread(s,'%d%d%d','delimiter','.')
year =
2008
month =
12
day =
1
And I checked in the matlab that both the "date" and "s" is a char array.(by using function 'ischar' and simply display both)...
But why do the strread() give differnt results?
Can anyone answer?
by the way, I use the MatLab v6.5.(for my own reason, so please don't comment by asking "why not use a higher version")....
Your problem is this line:
date = char(date);
It does not create an array of strings, there is no array of strings in matlab. It creates an array of chars. As you already noticed, your strread-line is fine if you input a single date, so input each date form your original cell array individually:
for idx=1:numel(date)
[year(idx),month(idx),day(idx)]=strread(date{idx},'%d%d%d','delimiter','.');
end
Preallocation of year, month and day improves the performance.
When trying the following concatenation:
for i=1:1:length(Open)
data(i,1) = Open(i);
data(i,2) = Close(i);
data(i,3) = High(i);
data(i,4) = Low(i);
data(i,5) = Volume(i);
data(i,6) = Adj_Close(i);
data(i,7) = cell2mat(dates(1,i));
end
Where all matrices but dates contain double values, and dates is a cell array with dates in the format '2001-01-01'. Running the code above, I get the following error:
??? Subscripted assignment dimension mismatch.
Error in ==> Test_Trades_part2 at 81
data(i,7) = cell2mat(dates(1,i));
The code above is tied to a master code which takes data from Yahoo Finance and then puts it in my SQL database.
A convenient way to store dates in completely numeric format is with datenum:
>> data(i,7) = datenum('2001-01-01');
>> disp(data(i,:))
0 0 0 0 0 0 730852
Whether this is useful to you depends on what you intend to do with the SQL database. Howeer, converting back to a string with MATLAB is straightforward with the datestr command:
>> datestr(730852,'yyyy-mm-dd')
ans =
2001-01-01
APPENDIX:
A serial date number represents a calendar date as the number of days that has passed since a fixed base date. In MATLAB, serial date number 1 is January 1, 0000.
Thank you all for the help!
I solved this issue using the following methodlogy (incorporating structs, should have thought of that .. stupid me):
data = [open, close_price, high, low, volume, closeadj];
s = struct('OpenPrice', data(:,1), 'ClosePrice', data(:,2), 'High', data(:,3), 'Low', data(:,4), 'Volume', data(:,5), 'Adj_Close', data(:,6), 'Dates', {dates});
This way, I enter all the values contained in the struct, circumventing the need to concatenate numeric and string matrices. Odd though, that is not allowed to have such matrices in on matrix; I would suppose that is the reason they created structs.