I would like to modify a string that will have make the first letter capitalized and all other letters lower cased, and anything else will be unchanged.
I tried this:
function new_string=switchCase(str1)
%str1 represents the given string containing word or phrase
str1Lower=lower(str1);
spaces=str1Lower==' ';
caps1=[true spaces];
%we want the first letter and the letters after space to be capital.
strNew1=str1Lower;
strNew1(caps1)=strNew1(caps1)-32;
end
This function works nicely if there is nothing other than a letter after space. If we have anything else for example:
str1='WOW ! my ~Code~ Works !!'
Then it gives
new_string =
'Wow My ^code~ Works !'
However, it has to give (according to the requirement),
new_string =
'Wow! My ~code~ Works !'
I found a code which has similarity with this problem. However, that is ambiguous. Here I can ask question if I don't understand.
Any help will be appreciated! Thanks.
Interesting question +1.
I think the following should fulfil your requirements. I've written it as an example sub-routine and broken down each step so it is obvious what I'm doing. It should be straightforward to condense it into a function from here.
Note, there is probably also a clever way to do this with a single regular expression, but I'm not very good with regular expressions :-) I doubt a regular expression based solution will run much faster than what I've provided (but am happy to be proven wrong).
%# Your example string
Str1 ='WOW ! my ~Code~ Works !!';
%# Convert case to lower
Str1 = lower(Str1);
%# Convert to ascii
Str1 = double(Str1);
%# Find an index of all locations after spaces
I1 = logical([0, (Str1(1:end-1) == 32)]);
%# Eliminate locations that don't contain lower-case characters
I1 = logical(I1 .* ((Str1 >= 97) & (Str1 <= 122)));
%# Check manually if the first location contains a lower-case character
if Str1(1) >= 97 && Str1(1) <= 122; I1(1) = true; end;
%# Adjust all appropriate characters in ascii form
Str1(I1) = Str1(I1) - 32;
%# Convert result back to a string
Str1 = char(Str1);
Related
I'd like to have a function generate(n) that generates the first n lowercase characters of the alphabet appended in a string (therefore: 1<=n<=26)
For example:
generate(3) --> 'abc'
generate(5) --> 'abcde'
generate(9) --> 'abcdefghi'
I'm new to Matlab and I'd be happy if someone could show me an approach of how to write the function. For sure this will involve doing arithmetic with the ASCII-codes of the characters - but I've no idea how to do this and which types that Matlab provides to do this.
I would rely on ASCII codes for this. You can convert an integer to a character using char.
So for example if we want an "e", we could look up the ASCII code for "e" (101) and write:
char(101)
'e'
This also works for arrays:
char([101, 102])
'ef'
The nice thing in your case is that in ASCII, the lowercase letters are all the numbers between 97 ("a") and 122 ("z"). Thus the following code works by taking ASCII "a" (97) and creating an array of length n starting at 97. These numbers are then converted using char to strings. As an added bonus, the version below ensures that the array can only go to 122 (ASCII for "z").
function output = generate(n)
output = char(97:min(96 + n, 122));
end
Note: For the upper limit we use 96 + n because if n were 1, then we want 97:97 rather than 97:98 as the second would return "ab". This could be written as 97:(97 + n - 1) but the way I've written it, I've simply pulled the "-1" into the constant.
You could also make this a simple anonymous function.
generate = #(n)char(97:min(96 + n, 122));
generate(3)
'abc'
To write the most portable and robust code, I would probably not want those hard-coded ASCII codes, so I would use something like the following:
output = 'a':char(min('a' + n - 1, 'z'));
...or, you can just generate the entire alphabet and take the part you want:
function str = generate(n)
alphabet = 'a':'z';
str = alphabet(1:n);
end
Note that this will fail with an index out of bounds error for n > 26, so you might want to check for that.
You can use the char built-in function which converts an interger value (or array) into a character array.
EDIT
Bug fixed (ref. Suever's comment)
function [str]=generate(n)
a=97;
% str=char(a:a+n)
str=char(a:a+n-1)
Hope this helps.
Qapla'
I have a string and I need two characters to be returned.
I tried with strsplit but the delimiter must be a string and I don't have any delimiters in my string. Instead, I always want to get the second number in my string. The number is always 2 digits.
Example: 001a02.jpg I use the fileparts function to delete the extension of the image (jpg), so I get this string: 001a02
The expected return value is 02
Another example: 001A43a . Return values: 43
Another one: 002A12. Return values: 12
All the filenames are in a matrix 1002x1. Maybe I can use textscan but in the second example, it gives "43a" as a result.
(Just so this question doesn't remain unanswered, here's a possible approach: )
One way to go about this uses splitting with regular expressions (MATLAB's strsplit which you mentioned):
str = '001a02.jpg';
C = strsplit(str,'[a-zA-Z.]','DelimiterType','RegularExpression');
Results in:
C =
'001' '02' ''
In older versions of MATLAB, before strsplit was introduced, similar functionality was achieved using regexp(...,'split').
If you want to learn more about regular expressions (abbreviated as "regex" or "regexp"), there are many online resources (JGI..)
In your case, if you only need to take the 5th and 6th characters from the string you could use:
D = str(5:6);
... and if you want to convert those into numbers you could use:
E = str2double(str(5:6));
If your number is always at a certain position in the string, you can simply index this position.
In the examples you gave, the number is always the 5th and 6th characters in the string.
filename = '002A12';
num = str2num(filename(5:6));
Otherwise, if the formating is more complex, you may want to use a regular expression. There is a similar question matlab - extracting numbers from (odd) string. Modifying the code found there you can do the following
all_num = regexp(filename, '\d+', 'match'); %Find all numbers in the filename
num = str2num(all_num{2}) %Convert second number from str
I'm a neuroscience/biomedical engineering major struggling with this whole MATLAB programming ordeal and so far, this website is the best teacher available to me right now. I am currently having trouble with one of my HW problems. What I need to do is take a phrase, find a specific word in it, then take a specific letter in it and increase that letter by the number indicated. In other words:
phrase = 'this homework is so hard'
word = 'so'
letter = 'o'
factor = 5
which should give me 'This homework is sooooo hard'
I got rid of my main error, though I really don;t know how. I exited MATLAB, then got back into it. Lo and behold, it magically worked.
function[out1] = textStretch(phrase, word, letter, stretch)
searchword= strfind(phrase, word);
searchletter strfind(hotdog, letter); %Looks for the letter in the word
add = (letter+stretch) %I was hoping this would take the letter and add to it, but that's not what it does
replace= strrep(phrase, word, add) %This would theoretically take the phrase, find the word and put in the new letter
out1 = replace
According to the teacher, the ones() function might be useful, and I have to concatenate strings, but if I can just find it in the string and replace it, why do I need to concatenate?
Since this is homework I won't write the whole thing out for you but you were on the right track with strfind.
a = strfind(phrase, word);
b = strfind(word, letter);
What does phrase(1:a) return? What does phrase(a+b:end) return?
Making some assumptions about why your teacher wants you to use ones:
What does num = double('o') return?
What does char(num) return? How about char([num num])?
You can concatenate strings like this:
out = [phrase(1:a),'ooooo',phrase(a+b:end)];
So all you really need to focus on is how to get a string which is letter repeated factor times.
If you wanted to use strrep instead you would need to give it the full word you are searching for and a copy of that word with the repeated letters in:
new_phrase = strrep(phrase, 'so', 'sooooo');
Again, the issue is how to get the 'sooooo' string.
See if this works for you -
phrase_split = regexp(phrase,'\s','Split'); %// Split into words as cells
wordr = cellstr(strrep(word,letter,letter(:,ones(1,factor))));%// Stretched word
phrase_split(strcmp(phrase_split,word)) = wordr;%//Put stretched word into place
out = strjoin(phrase_split) %// %// Output as the string cells joined together
Note: strjoin needs a recent MATLAB version, which if unavailable could be obtained from here.
Or you can just use a hack obtained from the m-file itself -
out = [repmat(sprintf(['%s', ' '], phrase_split{1:end-1}), ...
1, ~isscalar(phrase_split)), sprintf('%s', phrase_split{end})]
Sample run -
phrase =
this homework is so hard and so boring
word =
so
letter =
o
factor =
5
out =
this homework is sooooo hard and sooooo boring
So, just wrap the code into a function wrapper like this -
function out = textStretch(phrase, word, letter, factor)
Homework molded edit:
phrase = 'this homework is seriously hard'
word = 'seriously'
letter = 'r'
stretch = 6
out = phrase
stretched_word = letter(:,ones(1,stretch))
hotdog = strfind(phrase, word)
hotdog_st = strfind(word,letter)
start_ind = hotdog+hotdog_st-1
out(start_ind+stretch:end+stretch-1) = out(start_ind+1:end)
out(hotdog+hotdog_st-1:hotdog+hotdog_st-1+stretch-1) = stretched_word
Output -
out =
this homework is serrrrrriously hard
As again, use this syntax to convert to function -
function out = textStretch(phrase, word, letter, stretch)
Well Jessica first of all this is WRONG, but I am not here to give you the solution. Could you please just use it this way? This surely run.
function main_script()
phrase = 'this homework is so hard';
word = 'so';
letter = 'o';
factor = 5;
[flirty] = textStretchNEW(phrase, word, letter, factor)
end
function [flirty] = textStretchNEW(phrase, word, letter, stretch)
hotdog = strfind(phrase, word);
colddog = strfind(hotdog, letter);
add = letter + stretch;
hug = strrep(phrase, word, add);
flirty = hug
end
diary_file = tempname();
diary(diary_file);
myFun();
diary('off');
output = fileread(diary_file);
I would like to search a string from output, but also to ignore spaces and upper/lower cases. Here is an example for what's in output:
the test : passed
number : 4
found = 'thetest:passed'
a = strfind(output,found )
How could I ignore spaces and cases from output?
Assuming you are not too worried about accidentally matching something like: 'thetEst:passed' here is what you can do:
Remove all spaces and only compare lower case
found = 'With spaces'
found = lower(found(found ~= ' '))
This will return
found =
withspaces
Of course you would also need to do this with each line of output.
Another way:
regexpi(output(~isspace(output)), found, 'match')
if output is a single string, or
regexpi(regexprep(output,'\s',''), found, 'match')
for the more general case (either class(output) == 'cell' or 'char').
Advantages:
Fast.
robust (ALL whitespace (not just spaces) is removed)
more flexible (you can return starting/ending indices of the match, tokenize, etc.)
will return original case of the match in output
Disadvantages:
more typing
less obvious (more documentation required)
will return original case of the match in output (yes, there's two sides to that coin)
That last point in both lists is easily forced to lower or uppercase using lower() or upper(), but if you want same-case, it's a bit more involved:
C = regexpi(output(~isspace(output)), found, 'match');
if ~isempty(C)
C = found; end
for single string, or
C = regexpi(regexprep(output, '\s', ''), found, 'match')
C(~cellfun('isempty', C)) = {found}
for the more general case.
You can use lower to convert everything to lowercase to solve your case problem. However ignoring whitespace like you want is a little trickier. It looks like you want to keep some spaces but not all, in which case you should split the string by whitespace and compare substrings piecemeal.
I'd advertise using regex, e.g. like this:
a = regexpi(output, 'the\s*test\s*:\s*passed');
If you don't care about the position where the match occurs but only if there's a match at all, removing all whitespaces would be a brute force, and somewhat nasty, possibility:
a = strfind(strrrep(output, ' ',''), found);
I am trying to add '\' before all special characters in a string in MATLAB, could anyone please help me out. Here is the example:
tStr = 'Hi, I'm a Big (Not So Big) MATLAB addict; Since my school days!';
I want this string to be changed to:
'Hi\, I\'m a Big \(Not so Big \) MATLAB addict\; Since my school days\!'
The escape character in Matlab is the single quote ('), not the backslash (\), like in C language. Thus, your string must be like this:
tStr = 'Hi\, I\''m a Big (Not so Big ) MATLAB addict\; Since my school days!'
I took the list of special charecters defined on the Mathworks webpage to do this:
special = '[]{}()=''.().....,;:%%{%}!#';
tStr = 'Hi, I''m a Big (Not So Big) MATLAB addict; Since my school days!';
outStr = '';
for l = tStr
if (length(find(special == l)) > 0)
outStr = [outStr, '\', l];
else
outStr = [outStr, l];
end
end
which will automatically add those \s. You do need to use two single quotes ('') in place of the apostrophe in your input string. If tStr is obtained with the function input(), or something similar, this will procedure will still work.
Edited:
Or using regular expressions:
regexprep(tStr,'([[\]{}()=''.(),;:%%{%}!#])','\\$1')