I have a cell data type matrix containing a header and a large number of rows.
sample data:
set press dp
32.7045 17.805965 123.75047
32.690094 17.80584 123.74992
32.6232 17.815094 123.790115
I am trying to find the index of a specific column using the strcmp command to search through the all the data.
dpCol = strcmp([data{:}], 'dp')
This always returns
dpCol =
0
Am I using the data cell type wrong or something? Thank you!
Try using cell notation to yield just the 1st row, EG:
data(1,:) = {'set','press','dp'}
instead of unpacking* the entire cell array since strcmp can operate on cell arrays.
>>> data = {'set' 'press' 'dp'
32.7045 17.805965 123.75047
32.690094 17.80584 123.74992
32.6232 17.815094 123.790115}
data =
'set' 'press' 'dp'
[32.7045] [17.8060] [123.7505]
[32.6901] [17.8058] [123.7499]
[32.6232] [17.8151] [123.7901]
>>> col_idx = strcmp(data(1,:),'dp')
col_idx=
0 0 1
Then return the dp using the logical indices and cell2mat...
>>> dp = cell2mat(data(2:end,col_idx))
dp =
123.7505
123.7499
123.7901
or unpack* and concatenate the comma separated list
>>> dp = [data{2:end,col_idx}]
dp =
123.7505 123.7499 123.7901
As an alternative try cell2struct.
>>> datastruct = cell2struct(data(2:end,:),data(1,:),2)
datastruct =
3x1 struct array with fields:
set
press
dp
Then dp is ...
>>> dp = [datastruct.dp]
dp =
123.7505 123.7499 123.7901
* Using the colon operator inside curly braces unpacks an cell array into a comma separated list. Using square brackets horizontally concatenates the comma separated list which returns a character array set pressdp{{{ since the first item in the list is a character array. The garbage characters between and after 'set', 'press' and 'dp' are caused by reading the doubles as char. IE: char(32.7045) is the ASCII equivalent of whitespace. The arrays always get unpacked as column.
Related
I have a cell array with values similar to the following one
13:41:54.879
I would like to extract only 13:41 part of the given value and mitigate the rest. I tried various combinations of extractBefore() and extractAfter() but couldn't get it.
You can use a regular expression to match the pattern "digits, colon, digits":
c = {'13:41:54.879', '1:22:33.45679'};
result = regexp(c, '\d+:\d+', 'match', 'once');
gives
result =
1×2 cell array
{'13:41'} {'1:22'}
I have a 150X1 cell array. Within the array there are multiple data types. The first cell contains 0.9VA = 1.012207; the second: 0.9VA_CLK = 0.020752; and so on like this (for the most part). I would like to split the cell into two cells using the = as the delimiter. Thus, {1,1}: 0.9VA and {1,2}: 1.012207; {2,1}: 0.9VA_CLK and {2,2}: 0.020752; so on and so forth. I have tried converting them to strings and then using strsplit; however, I run into problems because the string arrays are variable in size.
If there is any other information that I can provide please let me know. Thank you for your help and time in advance.
You can indeed apply strsplit to each of the strings (char arrays) in the cell array. To do so, you can use cellfun:
c{1} = '0.9VA = 1.012207';
c{2} = '0.9VA_CLK = 0.020752';
c{3} = 'CSIPhgenSWoffList = [0, 0, 0, 0]';
c{4} = 'SomethingElse = [0.020752, 0.24564]';
c = cellfun(#(x)strsplit(x,'='),c,'UniformOutput',false);
c = cat(1,c{:});
I use a small example cell array c here, containing four strings, I hope this is representative. I apply strplit to each cell in c using cellfun(x,'='), which splits at the equal sign and returns a cell array with cell arrays. That is, each string in c is turned into a cell array with 2 strings (e.g. '0.9VA ' and ' 1.012207'. This does leave some spaces at the beginning and end of the strings.
The next line, cat, converts this cell array of cell arrays into a two-dimensional cell array. The final output is a cell array c containing the same number of rows as the original cell array, and with 2 columns. The first column corresponds to the part before the equal sign, the second column to the part after the equal sign.
To remove the spaces, you can use cellfun again, with strtrim:
c = cellfun(#strtrim,c,'UniformOutput',false);
I have a cell with value WORD = '00000'. But I just want to take the 4th and 5th value.
I already tried KATA=WORD(4:5),
I also tried KATA=WORD{4}
But still cannot.
I got this error message :
Index exceeds matrix dimensions.
How to split it? It's in <cell> type.
First you need to index the content of "first" (and only) cell element with curly brackets {} and then you can index the vector (). Therefore you need:
WORD = {'12345'}
output = WORD{1}(4:5)
which gives:
output =
45
You might have something like this
>> word = {'00000'};
This is a 1x1 cell array containing a 1x5 char array. To index into the char array, you first need to index into the cell array, which you do with
>> word{1}
ans =
00000
And now you can index the 4th and 5th element
>> word{1}(4:5)
ans =
00
I have a string in the following format :
fileName.jpg,10,20,10,10,...,12,14,True
Basically, I have a string with comma separated values. The first value is a string, then it follows an array of 100 values and lastly another string being true or false.
Is there a way or directly reading these values into 3 variable? Two strings and an array?
The array of values might contain n\a values which I want to treat as -1 or something similar or by using a cell array and having an empty cell for those? Can you recommend me something for this type of problem?
You can use textscan:
n = 100; % number of integers between filename and logical values
M = textscan(str, ['%s' repmat('%d',1, n) '%s'], 'delimiter', ',',...
'TreatAsEmpty', 'n\a', 'EmptyValue', -1, 'CollectOutput', true);
The result M is a cell array with the file name in the first cell, the 100 integer values in the second, and a string containing the logical value in the last cell.
You can use strsplit and extract the values from your String and store them in separate variables
Code Sample:
a = strsplit("fileName.jpg,10,20,10,10,...,12,14,True",",")
fileName = a(1)
flag = a(end)
data = a(2:end-1)
I am using xlsread in MATLAB to read in sheets from an excel file. My goal is to have each column of the excel sheet read as a numeric array. One of the columns has a mix of numbers and numbers+char. For example, the values could be 200, 300A, 450, 500A, 200A, 100. here is what I have so far:
[num, txt, raw] = xlsread(fileIn, sheets{ii}); % Reading in each sheet from a for loop
myCol = raw(:, 4) % I want all rows of column 4
for kk=1:numel(myCol)
if iscellstr(myCol(kk))
myCol(kk) = (cellfun(#(x)strrep(x, 'A', ''), myCol(kk), 'UniformOutput', false));
end
end
myCol = cell2mat(myCol);
This is able to strip off the char from the number but then I am left with:
myCol =
[200]
'300'
[450]
'500'
'200'
[100]
which errors out on cell2mat with:
cell2mat(myCol)
??? Error using ==> cell2mat at 46
All contents of the input cell array must be of the same data type.
I feel like I am probably mixing up () and {} somewhere. Can someone help me out with this?
Let me start from reading the file
[num, txt, raw] = xlsread('test.xlsx');
myCol = raw(:, 4);
idx = cellfun(#ischar,myCol ); %# find strings
data = zeros(size(myCol)); %# preallocate matrix for numeric data
data(~idx) = cell2mat(myCol(~idx)); %# convert numeric data
data(idx) = str2double(regexprep(myCol(idx),'\D','')); %# remove non-digits and convert to numeric
The variable myCol is initially a cell array containing both numbers and strings, something like this in your example:
myCol = {200; '300A'; 450; '500A'; '200A'; 100};
The steps you have to follow to convert the string entries into numeric values is:
Identify the cell entries in myCol that are strings. You can use a loop to do this, as in your example, or you can use the function CELLFUN to get a logical index like so:
index = cellfun(#ischar,myCol);
Remove the letters. If you know the letters to remove will always be 'A', as in your example, you can use a simple function like STRREP on all of your indexed cells like so:
strrep(myCol(index),'A','')
If you can have all sorts of other characters and letters in the string, then a function like REGEXPREP may work better for you. For your example, you could do this:
regexprep(myCol(index),'\D','')
Convert the strings of numbers to numeric values. You can do this for all of your indexed cells using the function STR2DOUBLE:
str2double(regexprep(myCol(index),'\D',''))
The final result of the above can then be combined with the original numeric values in myCol. Putting it all together, you get the following:
>> index = cellfun(#ischar,myCol);
>> result(index,1) = str2double(regexprep(myCol(index),'\D',''));
>> result(~index) = [myCol{~index}]
result =
200
300
450
500
200
100