I'm a java guy coming over to Objective-C. In java, to add a variable to a string you'd have to do something along the lines of:
someString = "This string is equal to " + someNumber + ".";
I can't figure out how to do it in Objective-C though. I have an NSMutableString that I'd like to add to the middle of a string. How do I go about doing this?
I've tried:
NSString *someText = #"Lorem ipsum " + someMutableString;
NSString *someText = #"Lorem ipsum " + [someMutableString stringForm];
and a few other things, none of which seem to work. Also interchanged the +s with ,s.
You can use appendString:, but in general, I prefer:
NSString *someText = [NSString stringWithFormat: #"Lorem ipsum %#", someMutableString];
NSString *someString = [NSString stringWithFormat: #"This is string is equal to %d.", someInt];
NSString *someOtherString = [NSString stringWithFormat: #"This is string is equal to %#.", someNSNumber];
or, alternatively:
NSString *someOtherString = [NSString stringWithFormat: #"This is string is equal to %d.", [someNSNumber intValue]];
etc...
These strings are autoreleased, so take care not to lose their value. If necessary, retain or copy them and release them yourself later.
Try this:
NSMutableString * string1 = [[NSMutableString alloc] initWithString:#"this is my string"];
[string1 appendString:#" with more strings attached"];
//release when done
[string1 release];
You need to use stringByAppendingString
NSString* string = [[NSString alloc] initWithString:#"some string"];
string = [string stringByAppendingString:#" Sweet!"];
Don't forget to [string release]; when your done of course.
NSMutableString *string = [[NSMutableString alloc] init];
[string appendFormat:#"more text %#", object ];
Related
I want to remove only first space in below string.
NSString *str = #"IF_Distance (GET_Mi mi=km*1.4,STRING1,STRING2)";
Note: There is a space after IF_Distance and another space after
GET_Mi. I am unable to remove the space after IF_Distance.
Use rangeOfString: to locate the first space, then use stringByReplacingCharactersInRange:withString: to replace it with the empty string.
Remove space by using below code.
NSString *str = #"IF_Distance (GET_Mi mi=km*1.4,STRING1,STRING2)";
NSString *secondString = [str stringByReplacingOccurrencesOfString:#"IF_Distance " withString:#"IF_Distance"];
Try This:
NSString *str = #"IF_Distance (GET_Mi mi=km*1.4,STRING1,STRING2)";
NSString *firstStringContainingSpace = [[str componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] firstObject];//firstStringContainingSpace = IF_Distance
str = [str stringByReplacingCharactersInRange:[str rangeOfString:[NSString stringWithFormat:#"%# ",firstStringContainingSpace]] withString:firstStringContainingSpace];
Output:
str = #"IF_Distance(GET_Mi mi=km*1.4,STRING1,STRING2)";
You can remove first space by using following code:
First find space by using rangeOfString: and then remove by using stringByReplacingCharactersInRange:withString: method.
Like,
NSString *str = #"IF_Distance (GET_Mi mi=km*1.4,STRING1,STRING2)";
NSString *strSpace = #" ";
NSRange range = [str rangeOfString:strSpace];
NSString *strFinal;
if (NSNotFound != range.location) {
strFinal = [str stringByReplacingCharactersInRange:range withString:#""];
}
If you are looking for some more universal way - this is the variant of it:
- (NSString *)removeWhitespaces:(NSString *)string {
NSMutableArray * stringComponents = [[string componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] mutableCopy];
NSString * fStringComponent = [stringComponents firstObject];
[stringComponents removeObject:fStringComponent];
return [fStringComponent stringByAppendingString:[stringComponents componentsJoinedByString:#" "]];
}
Is there a way to concatenate two strings and inject a character. I have :
NSString *firstString = #"http://www.stackoverflow.com";
NSString *secondString = #"supercooloptions";
NSString *result = [firstString stringByAppendingString: secondString];
NSLog(#"the final string with "/" injection = %#", result);
I'd like the final string with "/" injected = www.stackoverflow.com/supercooloptions
You can use a different method - for example, stringWithFormat:
NSString *result = [NSString stringWithFormat:#"%#/%#", firstString, secondString];
For this specific case, use stringByAppendingPathComponent:
NSString *result = [firstString stringByAppendingPathComponent:secondString];
I want to place a string within a string. Basically in pseudo code:
"first part of string" + "(varying string)" + "third part of string"
How can I do this in objective-c? Is there a way to easily concatenate in obj-c? Thanks!
Yes, do
NSString *str = [NSString stringWithFormat: #"first part %# second part", varyingString];
For concatenation you can use stringByAppendingString
NSString *str = #"hello ";
str = [str stringByAppendingString:#"world"]; //str is now "hello world"
For multiple strings
NSString *varyingString1 = #"hello";
NSString *varyingString2 = #"world";
NSString *str = [NSString stringWithFormat: #"%# %#", varyingString1, varyingString2];
//str is now "hello world"
Variations on a theme:
NSString *varying = #"whatever it is";
NSString *final = [NSString stringWithFormat:#"first part %# third part", varying];
NSString *varying = #"whatever it is";
NSString *final = [[#"first part" stringByAppendingString:varying] stringByAppendingString:#"second part"];
NSMutableString *final = [NSMutableString stringWithString:#"first part"];
[final appendFormat:#"%# third part", varying];
NSMutableString *final = [NSMutableString stringWithString:#"first part"];
[final appendString:varying];
[final appendString:#"third part"];
NSString * varyingString = ...;
NSString * cat = [NSString stringWithFormat:#"%s%#%#",
"first part of string",
varyingString,
#"third part of string"];
or simply -[NSString stringByAppendingString:]
You would normally use -stringWithFormat here.
NSString *myString = [NSString stringWithFormat:#"%#%#%#", #"some text", stringVariable, #"some more text"];
Just do
NSString* newString=[NSString stringWithFormat:#"first part of string (%#) third part of string", #"foo"];
This gives you
#"first part of string (foo) third part of string"
Iam amazed that none of the top answers pointed out that under recent Objective-C versions (after they added literals), you can concatenate just like this:
#"first" #"second"
And it will result in:
#"firstsecond"
You can not use it with NSString objects, only with literals, but it can be useful in some cases.
simple one:
[[#"first" stringByAppendingString:#"second"] stringByAppendingString:#"third"];
if you have many STRINGS to Concatenate, you should use NSMutableString for better performance
I want to import a file of strings line by line into an array. I want to get rid of all of the whitespace before and after the strings so that I can compare the strings a lot easier without having them not match due to small whitespace discrepancies. I NSData the content of the files then take the two strings
NSString* string = [[[NSString alloc] initWithBytes:[data bytes]
length:[data length]
encoding:NSUTF8StringEncoding] autorelease];
NSString* string2 = [[[NSString alloc] initWithBytes:[data2 bytes]
length:[data2 length]
encoding:NSUTF8StringEncoding] autorelease];
I tried below to remove the whitespace before adding to an array but it does not seem to work.
NSString *newString = [string stringByTrimmingCharactersInSet: [NSCharacterSet whitespaceCharacterSet]];
NSString *newString2 = [string2 stringByTrimmingCharactersInSet: [NSCharacterSet whitespaceCharacterSet]];
NSArray *fileInput = [newString componentsSeparatedByString:#"\n"];
NSArray *fileInput2 = [newString2 componentsSeparatedByString:#"\n"];
If you are looking at substituting all occurrences of whitespace then using stringByTrimmingCharactersInSet: won't help as it only trims off at the start and end of the string. You will need to use the stringByReplacingOccurrencesOfString:withString: method to eliminate the whitespace.
NSString * newString = [string stringByReplacingOccurrencesOfString:#" " withString:#""];
NSString * newString2 = [string2 stringByReplacingOccurrencesOfString:#" " withString:#""];
However,
If you want to trim all the strings in the array then you will have to enumerate the array and add the trimmed strings in a new mutable array.
Looks to me like you are removing the white space from the front and back of the whole file but not from each line. Try something like this;
NSArray *fileInput2 = [newString2 componentsSeparatedByString:#"\n"];
NSMutableArray *trimmedFileInput2 = [NSMutableArray array];
for(NSString *gak in fileInput2) {
[trimmedFileInput2 addObject:[gak stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
}
[Thanks #Deepak for the comment, dooh!]
Both #Deepak and #Bill Dudney being right, I'm just throwing in another way to solve your problem:
NSMutableArray *fileInput = [NSMutableArray array];
[string enumerateLinesUsingBlock:^(NSString *line, BOOL *stop) {
if ([line length] > 0) {
[fileInput addObject:
[line stringByTrimmingCharactersInSet:
[NSCharacterSet whitespaceCharacterSet]];
}
}];
(Disclaimer: Works in iOS 4+, OS X 10.6+ only... but I love blocks! :))
I have two NSString, A and B.
I would that A becomes B\nA.
How can I do?
If in a method I use
NSString *string_B = [[NSString alloc] initWithString:#"something_from_a_DB"];
NSString *string_A = [[NSString alloc] initWithString:#"something_from_a_DB"];
if (aTrueCondition) {
string_C = [NSString stringWithFormat:#"%#\n%#", string_B, string_A];
} else {
string_C = string_A;
}
is string_C = string_A; a memory leak or is it good?
I added [string_A release], as string_C is a retained property. Now it works.
This is the way to put them together:
NSString *newString = [NSString stringWithFormat:#"%#\n%#", stringB, stringA];
The second part is “A becoming newString”. This is hard to do, as regular strings are immutable in Cocoa. The best thing you can do is throw out the old A and point A to the new string:
NSString *strA = #"foo";
NSString *strB = #"bar";
strA = [NSString stringWith…];
Just be careful not to leak A:
NSString *strA = [[NSString alloc] initWithString:#"foo"];
strA = [NSString stringWith…]; // this is a leak
NSString *str=[NSString stringWithFormat:#"%#\n%#",B,A];
use this.
NSString *stringA = [NSString stringWithFormat:#"%#\n%#", stringB, stringA];