I have a character vector like so:
string = 'a(0:2), b(3), c(rand(4, 5)*0.1)';
I'd like to use this char array as input arguments to a function. The arguments would then be:
a(0:2)
b(3)
c(rand(4, 5)*0.1)
How can I parse the string into those input arguments?
At first glance, one could split the string with the ', ' separator, but it would fail for the third argument obviously.
A simple solution is using split as following:
expressions = split(string, "), ");
Then add ")" at the end of each string in expressions.
Related
(in swift language) For example " A + D " I want the string A to stay all the time but the value of D changes depending on let's say Hp, so when Hp is fd the string will be "A + fd" and etc
I mean like( "A + %s" % Hp ) for the string in python. Such as here: What does %s mean in Python?
If you are talking about %s, then it's a c-style formatting key, which awaits string variable or value in the list of arguments. In Swift, you compose strings using "\(variable)" syntax, which is called String interpolation, as explained in the documentation:
String Interpolation
String interpolation is a way to construct a new String value from a
mix of constants, variables, literals, and expressions by including
their values inside a string literal. You can use string interpolation
in both single-line and multiline string literals. Each item that you
insert into the string literal is wrapped in a pair of parentheses,
prefixed by a backslash ():
Source: official documentation
Example:
var myVar = "World"
var string = "Hello \(myVar)"
With non-strings:
let multiplier = 3
let message = "\(multiplier) times 2.5 is \(Double(multiplier) * 2.5)"
// Output: message is "3 times 2.5 is 7.5"
Can some one explain what this line here does? This is part of an old matlab code I need to reuse for my work
matdir = [params.ariens '-' num2str(dirtimes(ii))];
I'm especially confused about the '-' part. Thanks a lot in advance.
Single quotes are used to create a string literal so '-' simply creates a string containing the hyphen character. In MATLAB, [ ... ] performs horizontal concatenation so the line that you have shown concatenates the string stored in params.ariens, the character '-' and the number dirtimes(ii) converted to a string using num2str to creat one long string made up of those three strings.
For example:
c = ['abc', '-', 'def']
% abc-def
class(c)
% char
d = ['abc', '-', num2str(10)]
% abc-10
I have a scala program where I take "\t" as a command line input.
Inside the program I want to split a string on the basis of the delimiter passed from command line.
val splitter = args(0).charAt(0)
if(splitter == '\t')
println("true")
else
println("false")
This prints "false" and splitter "\".
The above method works for "," comma delimiter.
Please suggest how can I pass a tab or any other delimiter as command line parameter and use it for the splitting purpose.
It's because if you're passing "\t" in on the command line, then it's coming in as a two-character string \t, not a single-character tab. To do what you want, you can't just take the first character (charAt(0)) since you'll miss the t. Instead you'll have to unescape it by converting from the string \t to the tab character.
An easy way:
val splitter = args(0) match {
case "\\t" => '\t'
case x => x.head // same as x.charAt(0)
}
Could someone please tell me how to convert character array into a formatted output using Matlab?
I am expecting data like this:
CHAR (1 x 29) : 0.050822999 3.141592979 ; (1)
OR
CELL (1 x 1) or string: '0.050822999 3.141592979 ; (1)'
I am looking for output like this:
d1 = 0.050822999; %double
d2 = 3.141592979; %double
index = 1; % integer
I tried transposing and then using str2num(Str'); but, it's returning me 0x 0 double.
Any help would be appreciated.
Regards,
DK
you can use regexp to parse the string
c = { '0.050822999 3.141592979 ; (1)' };
p = regexp( c{1}, '^(\d+\.\d+)\s(\d+\.\d+)\s*;\s*\((\d+)\)$', 'tokens', 'once' ); %//parse the input string
numbers = str2mat(p); %// convert extracted strings to numerical values
Example result
ans =
0.050822999
3.141592979
1
Explaining the regexp pattern:
^ - pattern starts at the beginning of the input string
(\d+\.\d+) - parentheses ('()') enclosing this sub-pattern indicates it as a single token
\d+ matches one or more digits, then expecting \. a dot (notice the \, since . alone in regexp acts as a wildcard) and after the dot \d+ one or more digits are expected.
This token should correspond to the first number, e.g., 0.050822999
\s expecting a single space
(\d+\.\d+) - again, expecting another decimal fraction as the second token.
\s* - expecting white space (zero or more).
; - capture the ; in the expression, but not as a token.
\s+ - expecting white space (zero or more).
\( - expecting an open parenthesis, note the \ since parentheses in regexp are used to denote tokens.
(\d+) - expecting one or more digits as the third token, only integer numbers are expected here. no decimal point.
\) - expecting a closing parenthesis.
$ - pattern should reach the end of the input string.
You can use something like this (if I understood you correctly)
function str_dump(var)
info = whos;
disp([info.class ' ' mat2str(info.size) ' : ' var]);
end
This just shows information about the string. If you want to parse it and convert to another Matlab's structure, you have to explain it more carefully.
%// Input
a = [0.050822999 3.141592979];
n = 1;
%// Output
str = [num2str(a,'%0.9f ') ' ; (' num2str(n) ')']
Result:
str =
0.050822999 3.141592979 ; (1)
I have a cell array like:
>>text
'Sentence1'
'Sentence2'
'Sentence3'
Whenever I use
sprintf(fid,'%s\n',text)
I get an error saying:
'Function is not defined for 'cell' inputs.'
But if I put :
sprintf(fid,'%s\n',char(text))
It works but in the file appears all the sentences mixed all together like with no sense.
Can you recommend me what to do?
Whener I put text I get:
>>text
'Title '
'Author'
'comments '
{3x1} cell
That is why I can not use text{:}.
If you issue
sprintf('%s\n', text)
you are saying "print a string with a newline. The string is this cell array". That's not correct; a cell-array is not a string.
If you issue
sprintf('%s\n', char(text))
you are saying "print a string with a newline. The string is this cell array, which I convert to character array.". The thing is, that conversion results in a single character array, and sprintf will re-use the %s\n format only for multiple inputs. Moreover, it writes that single character array by column, meaning, all characters in the first column, concatenated horizontally with all characters from the second column, concatenated with all characters from the third column, etc.
Therefore, the approprate call to sprintf is something with multiple inputs:
sprintf(fid, '%s\n', text{:})
because the cell-expansion text{:} creates a comma-separated list from all entries in the cell-array, which is exactly what sprintf/fprintf expects.
EDIT As you indicate:, you have non-char entries in text. You have to check for that. If you want to pass only the strings into fprintf, use
fprintf(fid, '%s\n', text{ cellfun('isclass', text, 'char') })
if that {3x1 cell} is again a set of strings, so you want to write all strings recursively, then just use something like this:
function textWriter
text = {...
'Title'
'Author'
'comments'
{...
'Title2'
'Author2'
'comments2'
{...
'Title3'
'Author3'
'comments3'
}
}
}
text = cell2str(text);
fprintf(fid, '%s\n', text{:});
end
function out = cell2str(c)
out = {};
for ii = c(:)'
if iscell(ii{1})
S = cell2str(ii{1});
out(end+1:end+numel(S)) = S;
else
out{end+1} = ii{1};
end
end
end