I have a cell array of numbers (in string format) which I would like to convert to numbers in matlab. The thing is that they are double quoted and I cannot seem to use str2num to convert them.
a = {'"15"'; '"16"'; '"17"'; '"30"'; '"50"'}
Is there any way to do so or to remove the double quotations from the numbers? Thanks!
You need to manually remove the double-quote symbols. You can do that using cellfun to apply an anonymous function to each cell. Here are two possible ways:
The anonymous function simply strips off the first and last characters. This works if the double-quote symbols are always at those positions:
a = {'"15"'; '"16"'; '"17"'; '"30"'; '"50"'};
result = cellfun(#(x) str2double(x(2:end-1)), a);
If some strings may not contain the double-quote symbols, or may contain several in arbitrary positions, use an anonymous function that removes any occurrences of that symbol:
a = {'15'; '16'; '"17"'; '30"'; '"""50"""'};
result = cellfun(#(x) str2double(x(x~='"')), a);
Related
I want to read a string in Matlab (not an external text file) which has numerical values separated by commas, such as
a = {'1,2,3'}
and I'd like to store it in a vector as numbers. Is there any function which does that? I only find processes and functions used to do that with text files.
I think you're looking for sscanf
A = sscanf(str,formatSpec) reads data from str, converts it according
to the format specified by formatSpec, and returns the results in an
array. str is either a character array or a string scalar.
You can try the str2num function:
vec = str2num('1,2,3')
If you have to use the cell a, per your example, it would be: vec=str2num(a{1})
There are some security warnings in the documentation to consider so be cognizant of how your code is being employed.
Another, more flexible, option is textscan. It can handle strings as well as file handles.
Here's an example:
cellResult = textscan('1,2,3', '%f','delimiter',',');
vec = cellResult{1};
I will use the eval function to "evaluate" the vector. If that is the structure, I will also use the cell2mat to get the '1,2,3' text (this can be approached by other methods too.
% Generate the variable "a" that contains the "vector"
a = {'1,2,3'};
% Generate the vector using the eval function
myVector = eval(['[' cell2mat(a) ']']);
Let me know if this solution works for you
I have a few lines of text like this:
abc
def
ghi
and I want to assign these multiple lines to a Matlab variable for further processing.
I am copying these from very large text file and want to process it in Matlab Instead of saving the text into a file and then reading line by line for processing.
I tried to handle the above text lines as single string but am getting an error whilst trying to assign to a variable:
x = 'abc
def
ghi'
Error:
x = 'abc
|
Error: String is not terminated properly.
Any suggestions which could help me understand and solve the issue will be highly appreciated.
I frequently do this, namely copy text from elsewhere which I want to hard-code into a MATLAB script (in my case it's generally SQL code I want to manipulate and call from MATLAB).
To achieve this I have a helper function in clipboard2cellstr.m defined as follows:
function clipboard2cellstr
str = clipboard('paste');
str = regexprep(str, '''', ''''''); % Double any single quotes
strs = regexp(str, '\s*\r?\n\r?', 'split');
cs = sprintf('{\n''%s''\n}', strjoin(strs, sprintf('''\n''')));
clipboard('copy', cs);
disp(cs)
disp('(Copied to Clipboard)')
end
I then copy the text using Ctrl-c (or however) and run clipboard2cellstr. This changes the contents of the clipboard to something I can paste into the MATLAB editor using Ctrl-v (or however).
For example, copying this line
and this line
and this one, and then running the function generates this:
{
'For example, copying this line'
'and this line'
'and this one, and then running the function generates this:'
}
which is valid MATLAB which can be pasted directly in.
Your error is because you ended the line when MATLAB was expecting a closing quote character. You must use array notation to have multi-line or multi-element arrays.
You can assign like this if you use array notation
x = ['abc'
'def'
'hij']
>> x = 3×3 char array
Note: with this method, your rows must have the same number of characters, as you are really dealing with a character array. You can think of a character array like a numeric matrix, hence why it must be "rectangular".
If you have MATLAB R2016b or newer, you can use the string data type. This uses double quotes "..." rather than single quotes '...', and can be multi-line. You must still use array notation:
x = ["abc"
"def"
"hijk"]
>> x = 3×1 string array
We can have different numbers of characters in each line, as this is simply a 3 element string array, not a character array.
Alternatively, use a cell array of character arrays (or strings)
x = {'abc'
'def'
'hijk'}
>> x = 3×1 cell array
Again, you can have character arrays or strings of different lengths within a cell array.
In all of the above examples, a newline is simply for readability and can be replaced by a semi-colon ; to denote the next line of the array.
The option you choose will depend on what you want to do with the text. If you're reading from a file, I would suggest the string array or the cell array, as they can deal with different length lines. For backwards compatibility, use a cell array. You may find cellfun relevant for operating on cell arrays. For native string operations, use a string array.
I have a problem with splitting string into two parts on special character.
For example:
12345#data
or
1234567#data
I have 5-7 characters in first part separated with "#" from second part, where are another data (characters,numbers, doesn't matter what)
I need to store two parts on each side of # in two variables:
x = 12345
y = data
without "#" character.
I was looking for some Lua string function like splitOn("#") or substring until character, but I haven't found that.
Use string.match and captures.
Try this:
s = "12345#data"
a,b = s:match("(.+)#(.+)")
print(a,b)
See this documentation:
First of all, although Lua does not have a split function is its standard library, it does have string.gmatch, which can be used instead of a split function in many cases. Unlike a split function, string.gmatch takes a pattern to match the non-delimiter text, instead of the delimiters themselves
It is easily achievable with the help of a negated character class with string.gmatch:
local example = "12345#data"
for i in string.gmatch(example, "[^#]+") do
print(i)
end
See IDEONE demo
The [^#]+ pattern matches one or more characters other than # (so, it "splits" a string with 1 character).
I wanted to know how to remove first character of a string in octave. I am manipulating the string in a loop and after every loop, I want to remove the first character of the remaining string.
Thanks in advance.
If it's just a one-line string then:
short_string = long_string(2:end)
But if you have a cell array of strings then either do it as above if you have a loop already, otherwise you can use this shorthand to do it in one line:
short_strings = cellfun(#(x)(x(2:end)), long_strings, 'uni', false)
Or else if you have a matrix of strings (i.e. all the same length), then you can vectorize it as:
short_strings = long_strings(:, 2:end)
Trying to make a textfield where people write the unicode without the backslash. I want to add the backslash after they typed it. So the user types u2605 and the code converts it to "\u2605", i then convert this to a unicode character and insert it in textflow.
My code:
this works:
span.text = publicFunctions.htmlUnescape(he.encode("\u2605"))
this doesn't work:
span.text = publicFunctions.htmlUnescape(he.encode("\\u"+"2605"))
how to make a string that acts as a unicode string?
Tried all sorts of things, escape(unescape()), convert to number, "\u", "\u" ... nothing helps.
trace("\u2605" == "\u"+"2605") ... will return false. So will
trace("\u2605" == "\u"+"2605")
"\u2605" is a string with a single character, the character with the code point 2605, while "\\u" + "2605" is a string with 6 characters (the backslash, the u and the four digit number).
If you want to construct a unicode character from just the four digits, you should be able to use String.fromCharCode. The thing is just that the escape sequence uses a hexadecimal number, while the method obviously takes a decimal number. So if the user enters a hexadecimal string, you will have to convert that first:
trace(String.fromCharCode(parseInt('2605', 16)) == '\u2605'));
That's an interesting issue! I don't think you can concatenate a string literal and achieve what you're trying to do. The relevant character escaping happens when the string literal is originally formed, which means that you need the whole sequence together in the first place.
But you should be able to take the user-supplied number and dynamically generate a Unicode string with String.fromCharCode(...).
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/String.html#fromCharCode()