I'm trying to check the suffix of a string against a character set but I'm getting errors:
if ([string hasSuffix:[NSCharacterSet characterSetWithCharactersInString:#"(+-*/"])
What am I doing wrong, is there a correct alternative?
-[NSString hasSuffix:] takes an NSString as its argument, not an NSCharacterSet. Your best bet is probably to call -[NSString rangeOfCharacterFromSet:options:] with NSBackwardsSearch as an option and check that the location is at the end of the string.
What are you trying to do?
I think that you are trying to see if the first letter of your string is one of the characters from the set. If so, then use this:
NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:#"(+-*/"];
if ([[string substringToIndex:1] rangeOfCharacterFromSet:set].location != NSNotFound)
// String starts with one of the characters from the character set
Related
i have a NSString with parentheses in it.
I would like to remove the Text inside of the parentheses.
How to do that? ( In Objective-C )
Example String:
Tach auch. (lockeres Ruhrdeutsch) Und Hallo!
I would like to Remove "(lockeres Ruhrdeutsch)" from the String,
but the Strings i have to edit are always different.
How can i remove the String betweeen "(" and ")"?
Best Regards
Use regular expression:
NSString *string = #"Tach auch. (lockeres Ruhrdeutsch) Und Hallo!";
NSString *filteredString = [string stringByReplacingOccurrencesOfString:#"\\(.*\\)"
withString:#""
options:NSRegularExpressionSearch range:NSMakeRange(0, string.length)];
NSLog(#"%#", filteredString);
If you want to consider also a whitespace character after the closing parenthesis, add \\s? to the end of the regex pattern.
Here is the function you can call to get your required string:
-(NSString*)getStringWithBlankParaFrom:(NSString*)oldStr{
NSArray*strArray1=[oldStr componentsSeparatedByString:#"("];
NSString*str2=[strArray1 objectAtIndex:1];
NSArray*strArray2 =[str2 componentsSeparatedByString:#")"];
NSString*strToReplace=[strArray2 objectAtIndex:0];
return [oldStr stringByReplacingOccurrencesOfString:strToReplace withString:#""];
}
This function is valid for the string which contains one pair of parentheses**()**
You can change it as per your requirement.
Hope this helps!
I'm facing a problem when I try to remove a character in a 'NSString'. The character is a backend (\n).
My 'NSString' is for example like this :
My text is
also in a second line
And I want to get all in one line like this :
My text is also in a second line
The problem is I don't know how to change this...
I tried to locate the '\n' characters with a loop :
for (int delete = 0; delete < myString.length; delete++)
{
if ([myString characterAtIndex:delete] == 10)
{
[myString stringByReplacingCharactersInRange:NSMakeRange(delete,0) withString:#" "];
}
}
Or things like :
myString = [myString stringByReplacingOccurrencesOfString:#"\r" withString:#" "];
(I see that \r could be the backend in a nslog...)
Nothings work..
Thank you for your help in advance !
myString = [myString stringByReplacingOccurrencesOfString:#"\n" withString:#""];
is correct.
If it doesn't work, then the assumption that there is a combination of "\" and "n" characters is wrong.
Do not use NSLog. NSLog already applies carriage returns to the string. Instead put a breakpoint on the line where we call stringByReplacing... and then hover over the myString. Wait a second or two and you will see the "original unformatted content"...this way you can check what you are really trying to replace..
So I imagine that I need a regex statement to do this but I haven't had to do any regex with objective c yet, and I haven't written a regex statement in like a year.
I think it should be like ((?=.*[0-9]).{7,1000})
How do I put this into an objective c string comparison and evaluate the results?
Also is my regex correct?
While a regular expression would probably work, there is another approach:
NSString *str = // some string to check for at least one digit and a length of at least 7
if (str.length >= 7 && [str rangeOfCharacterFromSet:[NSCharacterSet decimalDigitCharacterSet]].location != NSNotFound) {
// this matches the criteria
}
This code actually checks more than just 0-9. It handles digits from other languages too. If you really just want 0-9 then replace:
[NSCharacterSet decimalDigitCharacterSet]
with:
[NSCharacterSet characterSetWithCharactersInString:#"0123456789"];
I am making an app where there is a requirement to store ASCII art into a database. I store the strings in the below format.
"___________\n |---------|-O\n/___________\\n|______________|\n\____________/"
When I retrieve the data and display it in a label, I want the newline characters and backslashes to be parsed so as to display the real shape of the ASCII art.
How should I parse this kind of strings?
NSString has a method to do what you want, which is to replace a litteral \n, with a newline character (which is symbolized as \n). In a c-format string you can use a double slash to let the library know the second slach is a real one and not an escape symbol. So this should work assuming you have been able to load your data from sqlite into an NSString:
newString = [yourStringFromSQLite stringByReplacingOccurrencesOfString:#"\\n" withString:#"\n"];
If you are using \n just for creating new lines then instead of that just keep space while inserting value in database and set following properties for label ->
1)keep width just to fit first word.
2)linebreakmode to wordwrap (so as width will not be available it will wrap next word to new line)
3)set no. of lines to 0
Hope this will help.
try to use the scanner for remove the html entities
- (NSString *)flattenHTML:(NSString *)html trimWhiteSpace:(BOOL)trim {
NSScanner *theScanner;
NSString *text = nil;
theScanner = [NSScanner scannerWithString:html];
while ([theScanner isAtEnd] == NO) {
[theScanner scanUpToString:#"<" intoString:NULL] ;
[theScanner scanUpToString:#">" intoString:&text] ;
html = [html stringByReplacingOccurrencesOfString:[ NSString stringWithFormat:#"%#>", text] withString:#" "];
}
return trim ? [html stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] : html;
}
and call this method where your trimmed string need to display
In Objective-C for iOS, how would I remove the last character of a string using a button action?
In your controller class, create an action method you will hook the button up to in Interface Builder. Inside that method you can trim your string like this:
if ([string length] > 0) {
string = [string substringToIndex:[string length] - 1];
} else {
//no characters to delete... attempting to do so will result in a crash
}
If you want a fancy way of doing this in just one line of code you could write it as:
string = [string substringToIndex:string.length-(string.length>0)];
*Explanation of fancy one-line code snippet:
If there is a character to delete (i.e. the length of the string is greater than 0)
(string.length>0) returns 1 thus making the code return:
string = [string substringToIndex:string.length-1];
If there is NOT a character to delete (i.e. the length of the string is NOT greater than 0)
(string.length>0) returns 0 thus making the code return:
string = [string substringToIndex:string.length-0];
Which prevents crashes.
If it's an NSMutableString (which I would recommend since you're changing it dynamically), you can use:
[myString deleteCharactersInRange:NSMakeRange([myRequestString length]-1, 1)];
The solutions given here actually do not take into account multi-byte Unicode characters ("composed characters"), and could result in invalid Unicode strings.
In fact, the iOS header file which contains the declaration of substringToIndex contains the following comment:
Hint: Use with rangeOfComposedCharacterSequencesForRange: to avoid breaking up composed characters
See how to use rangeOfComposedCharacterSequenceAtIndex: to delete the last character correctly.
The documentation is your friend, NSString supports a call substringWithRange that can shorten the string that you have an return the shortened String. You cannot modify an instance of NSString it is immutable. If you have an NSMutableString is has a method called deleteCharactersInRange that can modify the string in place
...
NSRange r;
r.location = 0;
r.size = [mutable length]-1;
NSString* shorted = [stringValue substringWithRange:r];
...