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:#" "]];
}
I need to parse a string like [abc]000, and what I want to get is an array containing abc and 000. Is there an easy way to do it?
I'm using code like this:
NSString *sampleString = #"[abc]000";
NSArray *sampleParts = [sampleString componentsSeparatedByString:#"]"];
NSString *firstPart = [[[sampleParts objectAtIndex:0] componentsSeparatedByString:#"["] lastObject];
NSString *lastPart = [sampleParts lastObject];
But it's inefficient and didn't check whether the string is in a format like [**]**.
For this simple pattern, can just parse yourself like:
NSString *s = #"[abc]000";
NSString *firstPart = nil;
NSString *lastPart = nil;
if ([s characterAtIndex: 0] == '[') {
NSUInteger i = [s rangeOfString:#"]"].location;
if (i != NSNotFound) {
firstPart = [s substringWithRange:NSMakeRange(1, i - 1)];
lastPart = [s substringFromIndex:i + 1];
}
}
Or you could learn to use the NSScanner class.
As always, there are lots of ways to do this.
OPTION 1
If these are fixed length strings (each part is always three characters) then you can simply get the substrings directly:
NSString *sampleString = #"[abc]000";
NSString *left = [sampleString substringWithRange:NSMakeRange(1, 3)];
NSString *right = [sampleString substringWithRange:NSMakeRange(5, 3)];
NSArray *parts = #[ left, right ];
NSLog(#"%#", parts);
OPTION 1 (shortened)
NSArray *parts = #[ [sampleString substringWithRange:NSMakeRange(1, 3)],
[sampleString substringWithRange:NSMakeRange(5, 3)] ];
NSLog(#"%#", parts);
OPTION 2
If they aren't always three characters, then you can use NSScanner:
NSString *sampleString = #"[abc]000";
NSScanner *scanner = [NSScanner scannerWithString:sampleString];
// Skip the first character if we know that it will always start with the '['.
// If we can not make this assumption, then we would scan for the bracket instead.
scanner.scanLocation = 1;
NSString *left, *right;
// Save the characters until the right bracket into a string which we store in left.
[scanner scanUpToString:#"]" intoString:&left];
// Skip the right bracket
scanner.scanLocation++;
// Scan to the end (You can use any string for the scanUpToString that doesn't actually exist...
[scanner scanUpToString:#"\0" intoString:&right];
NSArray *parts = #[ left, right ];
NSLog(#"%#", parts);
RESULTS (for all options)
2013-05-10 00:25:02.031 Testing App[41906:11f03] (
abc,
000
)
NOTE
All of these assume well-formed strings, so you should include your own error checking.
try like this ,
NSString *sampleString = #"[abc]000";
NSString *pNRegex = #"\\[[a-z]{3}\\][0-9]{3}";
NSPredicate *PNTest = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", pNRegex];
BOOL check=[PNTest evaluateWithObject:sampleString ];
NSLog(#"success:%i",check);
if success comes as 1 then you can perform the action for separating string into array.
I have a search string, where people can use quotes to group phrases together, and mix this with individual keywords. For example, a string like this:
"Something amazing" rooster
I'd like to separate that into an NSArray, so that it would have Something amazing (without quotes) as one element, and rooster as the other.
Neither componentsSeparatedByString nor componentsSeparatedByCharactersInSet seem to fit the bill. Is there an easy way to do this, or should I just code it up myself?
You probably will have to code some of this up yourself, but the NSScanner should be a good basis on which to build. If you use the scanUpToCharactersInSet method to look for everything up to your next whitespace or quote character to can pick off words. Once you encounter a quite character, you could continue to scan using just the quote in the character set to end at, so that spaces within the quotes don't result in the end of a token.
I made a simple way to do this using NSScanner:
+ (NSArray *)arrayFromTagString:(NSString *)string {
NSScanner *scanner = [NSScanner scannerWithString:string];
NSString *substring;
NSMutableArray *array = [[NSMutableArray alloc] init];
while (scanner.scanLocation < string.length) {
// test if the first character is a quote
unichar character = [string characterAtIndex:scanner.scanLocation];
if (character == '"') {
// skip the first quote and scan everything up to the next quote into a substring
[scanner setScanLocation:(scanner.scanLocation + 1)];
[scanner scanUpToString:#"\"" intoString:&substring];
[scanner setScanLocation:(scanner.scanLocation + 1)]; // skip the second quote too
}
else {
// scan everything up to the next space into the substring
[scanner scanUpToString:#" " intoString:&substring];
}
// add the substring to the array
[array addObject:substring];
//if not at the end, skip the space character before continuing the loop
if (scanner.scanLocation < string.length) [scanner setScanLocation:(scanner.scanLocation + 1)];
}
return array.copy;
}
This method will convert the array back to a tag string, re-quoting the multi-word tags:
+ (NSString *)tagStringFromArray:(NSArray *)array {
NSMutableString *string = [[NSMutableString alloc] init];
NSRange range;
for (NSString *substring in array) {
if (string.length > 0) {
[string appendString:#" "];
}
range = [substring rangeOfString:#" "];
if (range.location != NSNotFound) {
[string appendFormat:#"\"%#\"", substring];
}
else [string appendString:substring];
}
return string.description;
}
I ended up going with a regular expression as I was already using RegexKitLite, and creating this NSString+SearchExtensions category.
.h:
// NSString+SearchExtensions.h
#import <Foundation/Foundation.h>
#interface NSString (SearchExtensions)
-(NSArray *)searchParts;
#end
.m:
// NSString+SearchExtensions.m
#import "NSString+SearchExtensions.h"
#import "RegexKitLite.h"
#implementation NSString (SearchExtensions)
-(NSArray *)searchParts {
__block NSMutableArray *items = [[NSMutableArray alloc] initWithCapacity:5];
[self enumerateStringsMatchedByRegex:#"\\w+|\"[\\w\\s]*\"" usingBlock: ^(NSInteger captureCount,
NSString * const capturedStrings[captureCount],
const NSRange capturedRanges[captureCount],
volatile BOOL * const stop) {
NSString *result = [capturedStrings[0] stringByReplacingOccurrencesOfRegex:#"\"" withString:#""];
NSLog(#"Match: '%#'", result);
[items addObject:result];
}];
return [items autorelease];
}
#end
This returns an NSArray of strings with the search strings, removing the double quotes that surround the phrases.
If you'll allow a slightly different approach, you could try Dave DeLong's CHCSVParser. It is intended to parse CSV strings, but if you set the space character as the delimiter, I am pretty sure you will get the intended behavior.
Alternatively, you can peek into the code and see how it handles quoted fields - it is published under the MIT license.
I would run -componentsSeparatedByString:#"\"" first, then create a BOOL isPartOfQuote, initialized to YES if the first character of the string was a ", but otherwise set to NO.
Then create a mutable array to return:
NSMutableArray* masterArray = [[NSMutableArray alloc] init];
Then, create a loop over the array returned from the separation:
for(NSString* substring in firstSplitArray) {
NSArray* secondSplit;
if (isPartOfQuote == NO) {
secondSplit = [substring componentsSeparatedByString:#" "];
}
else {
secondSplit = [NSArray arrayWithObject: substring];
}
[masterArray addObjectsFromArray: secondSplit];
isPartOfQuote = !isPartOfQuote;
}
Then return masterArray from the function.
Are there any shortcuts to (stringByAppendingString:) string concatenation in Objective-C, or shortcuts for working with NSString in general?
For example, I'd like to make:
NSString *myString = #"This";
NSString *test = [myString stringByAppendingString:#" is just a test"];
something more like:
string myString = "This";
string test = myString + " is just a test";
An option:
[NSString stringWithFormat:#"%#/%#/%#", one, two, three];
Another option:
I'm guessing you're not happy with multiple appends (a+b+c+d), in which case you could do:
NSLog(#"%#", [Util append:one, #" ", two, nil]); // "one two"
NSLog(#"%#", [Util append:three, #"/", two, #"/", one, nil]); // three/two/one
using something like
+ (NSString *) append:(id) first, ...
{
NSString * result = #"";
id eachArg;
va_list alist;
if(first)
{
result = [result stringByAppendingString:first];
va_start(alist, first);
while (eachArg = va_arg(alist, id))
result = [result stringByAppendingString:eachArg];
va_end(alist);
}
return result;
}
Two answers I can think of... neither is particularly as pleasant as just having a concatenation operator.
First, use an NSMutableString, which has an appendString method, removing some of the need for extra temp strings.
Second, use an NSArray to concatenate via the componentsJoinedByString method.
If you have 2 NSString literals, you can also just do this:
NSString *joinedFromLiterals = #"ONE " #"MILLION " #"YEARS " #"DUNGEON!!!";
That's also useful for joining #defines:
#define STRINGA #"Also, I don't know "
#define STRINGB #"where food comes from."
#define JOINED STRINGA STRINGB
Enjoy.
I keep returning to this post and always end up sorting through the answers to find this simple solution that works with as many variables as needed:
[NSString stringWithFormat:#"%#/%#/%#", three, two, one];
For example:
NSString *urlForHttpGet = [NSString stringWithFormat:#"http://example.com/login/username/%#/userid/%i", userName, userId];
Create a method:
- (NSString *)strCat: (NSString *)one: (NSString *)two
{
NSString *myString;
myString = [NSString stringWithFormat:#"%#%#", one , two];
return myString;
}
Then, in whatever function you need it in, set your string or text field or whatever to the return value of this function.
Or, to make a shortcut, convert the NSString into a C++ string and use the '+' there.
Well, as colon is kind of special symbol, but is part of method signature, it is possible to exted the NSString with category to add this non-idiomatic style of string concatenation:
[#"This " : #"feels " : #"almost like " : #"concatenation with operators"];
You can define as many colon separated arguments as you find useful... ;-)
For a good measure, I've also added concat: with variable arguments that takes nil terminated list of strings.
// NSString+Concatenation.h
#import <Foundation/Foundation.h>
#interface NSString (Concatenation)
- (NSString *):(NSString *)a;
- (NSString *):(NSString *)a :(NSString *)b;
- (NSString *):(NSString *)a :(NSString *)b :(NSString *)c;
- (NSString *):(NSString *)a :(NSString *)b :(NSString *)c :(NSString *)d;
- (NSString *)concat:(NSString *)strings, ...;
#end
// NSString+Concatenation.m
#import "NSString+Concatenation.h"
#implementation NSString (Concatenation)
- (NSString *):(NSString *)a { return [self stringByAppendingString:a];}
- (NSString *):(NSString *)a :(NSString *)b { return [[self:a]:b];}
- (NSString *):(NSString *)a :(NSString *)b :(NSString *)c
{ return [[[self:a]:b]:c]; }
- (NSString *):(NSString *)a :(NSString *)b :(NSString *)c :(NSString *)d
{ return [[[[self:a]:b]:c]:d];}
- (NSString *)concat:(NSString *)strings, ...
{
va_list args;
va_start(args, strings);
NSString *s;
NSString *con = [self stringByAppendingString:strings];
while((s = va_arg(args, NSString *)))
con = [con stringByAppendingString:s];
va_end(args);
return con;
}
#end
// NSString+ConcatenationTest.h
#import <SenTestingKit/SenTestingKit.h>
#import "NSString+Concatenation.h"
#interface NSString_ConcatenationTest : SenTestCase
#end
// NSString+ConcatenationTest.m
#import "NSString+ConcatenationTest.h"
#implementation NSString_ConcatenationTest
- (void)testSimpleConcatenation
{
STAssertEqualObjects([#"a":#"b"], #"ab", nil);
STAssertEqualObjects([#"a":#"b":#"c"], #"abc", nil);
STAssertEqualObjects([#"a":#"b":#"c":#"d"], #"abcd", nil);
STAssertEqualObjects([#"a":#"b":#"c":#"d":#"e"], #"abcde", nil);
STAssertEqualObjects([#"this " : #"is " : #"string " : #"concatenation"],
#"this is string concatenation", nil);
}
- (void)testVarArgConcatenation
{
NSString *concatenation = [#"a" concat:#"b", nil];
STAssertEqualObjects(concatenation, #"ab", nil);
concatenation = [concatenation concat:#"c", #"d", concatenation, nil];
STAssertEqualObjects(concatenation, #"abcdab", nil);
}
Use stringByAppendingString: this way:
NSString *string1, *string2, *result;
string1 = #"This is ";
string2 = #"my string.";
result = [result stringByAppendingString:string1];
result = [result stringByAppendingString:string2];
OR
result = [result stringByAppendingString:#"This is "];
result = [result stringByAppendingString:#"my string."];
Macro:
// stringConcat(...)
// A shortcut for concatenating strings (or objects' string representations).
// Input: Any number of non-nil NSObjects.
// Output: All arguments concatenated together into a single NSString.
#define stringConcat(...) \
[#[__VA_ARGS__] componentsJoinedByString:#""]
Test Cases:
- (void)testStringConcat {
NSString *actual;
actual = stringConcat(); //might not make sense, but it's still a valid expression.
STAssertEqualObjects(#"", actual, #"stringConcat");
actual = stringConcat(#"A");
STAssertEqualObjects(#"A", actual, #"stringConcat");
actual = stringConcat(#"A", #"B");
STAssertEqualObjects(#"AB", actual, #"stringConcat");
actual = stringConcat(#"A", #"B", #"C");
STAssertEqualObjects(#"ABC", actual, #"stringConcat");
// works on all NSObjects (not just strings):
actual = stringConcat(#1, #" ", #2, #" ", #3);
STAssertEqualObjects(#"1 2 3", actual, #"stringConcat");
}
Alternate macro: (if you wanted to enforce a minimum number of arguments)
// stringConcat(...)
// A shortcut for concatenating strings (or objects' string representations).
// Input: Two or more non-nil NSObjects.
// Output: All arguments concatenated together into a single NSString.
#define stringConcat(str1, str2, ...) \
[#[ str1, str2, ##__VA_ARGS__] componentsJoinedByString:#""];
When building requests for web services, I find doing something like the following is very easy and makes concatenation readable in Xcode:
NSString* postBody = {
#"<?xml version=\"1.0\" encoding=\"utf-8\"?>"
#"<soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">"
#" <soap:Body>"
#" <WebServiceMethod xmlns=\"\">"
#" <parameter>test</parameter>"
#" </WebServiceMethod>"
#" </soap:Body>"
#"</soap:Envelope>"
};
Shortcut by creating AppendString (AS) macro ...
#define AS(A,B) [(A) stringByAppendingString:(B)]
NSString *myString = #"This";
NSString *test = AS(myString,#" is just a test");
Note:
If using a macro, of course just do it with variadic arguments, see EthanB's answer.
NSString *label1 = #"Process Name: ";
NSString *label2 = #"Process Id: ";
NSString *processName = [[NSProcessInfo processInfo] processName];
NSString *processID = [NSString stringWithFormat:#"%d", [[NSProcessInfo processInfo] processIdentifier]];
NSString *testConcat = [NSString stringWithFormat:#"%# %# %# %#", label1, processName, label2, processID];
Here's a simple way, using the new array literal syntax:
NSString * s = [#[#"one ", #"two ", #"three"] componentsJoinedByString:#""];
^^^^^^^ create array ^^^^^
^^^^^^^ concatenate ^^^^^
NSString *myString = #"This";
NSString *test = [myString stringByAppendingString:#" is just a test"];
After a couple of years now with Objective C I think this is the best way to work with Objective C to achieve what you are trying to achieve.
Start keying in "N" in your Xcode application and it autocompletes to "NSString".
key in "str" and it autocompletes to "stringByAppendingString". So the keystrokes are quite limited.
Once you get the hang of hitting the "#" key and tabbing the process of writing readable code no longer becomes a problem. It is just a matter of adapting.
The only way to make c = [a stringByAppendingString: b] any shorter is to use autocomplete at around the st point. The + operator is part of C, which doesn't know about Objective-C objects.
How about shortening stringByAppendingString and use a #define:
#define and stringByAppendingString
Thus you would use:
NSString* myString = [#"Hello " and #"world"];
Problem is that it only works for two strings, you're required to wrap additional brackets for more appends:
NSString* myString = [[#"Hello" and: #" world"] and: #" again"];
NSString *result=[NSString stringWithFormat:#"%# %#", #"Hello", #"World"];
NSString *label1 = #"Process Name: ";
NSString *label2 = #"Process Id: ";
NSString *processName = [[NSProcessInfo processInfo] processName];
NSString *processID = [NSString stringWithFormat:#"%d", [[NSProcessInfo processInfo] processIdentifier]];
NSString *testConcat = [NSString stringWithFormat:#"%# %# %# %#", label1, processName, label2, processID];
I tried this code. it's worked for me.
NSMutableString * myString=[[NSMutableString alloc]init];
myString=[myString stringByAppendingString:#"first value"];
myString=[myString stringByAppendingString:#"second string"];
Was trying the following in the lldb pane
[NSString stringWithFormat:#"%#/%#/%#", three, two, one];
which errors.
instead use alloc and initWithFormat method:
[[NSString alloc] initWithFormat:#"%#/%#/%#", #"three", #"two", #"one"];
This is for better logging, and logging only - based on dicius excellent multiple argument method. I define a Logger class, and call it like so:
[Logger log: #"foobar ", #" asdads ", theString, nil];
Almost good, except having to end the var args with "nil" but I suppose there's no way around that in Objective-C.
Logger.h
#interface Logger : NSObject {
}
+ (void) log: (id) first, ...;
#end
Logger.m
#implementation Logger
+ (void) log: (id) first, ...
{
// TODO: make efficient; handle arguments other than strings
// thanks to #diciu http://stackoverflow.com/questions/510269/how-do-i-concatenate-strings-in-objective-c
NSString * result = #"";
id eachArg;
va_list alist;
if(first)
{
result = [result stringByAppendingString:first];
va_start(alist, first);
while (eachArg = va_arg(alist, id))
{
result = [result stringByAppendingString:eachArg];
}
va_end(alist);
}
NSLog(#"%#", result);
}
#end
In order to only concat strings, I'd define a Category on NSString and add a static (+) concatenate method to it that looks exactly like the log method above except it returns the string. It's on NSString because it's a string method, and it's static because you want to create a new string from 1-N strings, not call it on any one of the strings that are part of the append.
NSNumber *lat = [NSNumber numberWithDouble:destinationMapView.camera.target.latitude];
NSNumber *lon = [NSNumber numberWithDouble:destinationMapView.camera.target.longitude];
NSString *DesconCatenated = [NSString stringWithFormat:#"%#|%#",lat,lon];
Try stringWithFormat:
NSString *myString = [NSString stringWithFormat:#"%# %# %# %d", "The", "Answer", "Is", 42];
When dealing with strings often I find it easier to make the source file ObjC++, then I can concatenate std::strings using the second method shown in the question.
std::string stdstr = [nsstr UTF8String];
//easier to read and more portable string manipulation goes here...
NSString* nsstr = [NSString stringWithUTF8String:stdstr.c_str()];
My preferred method is this:
NSString *firstString = #"foo";
NSString *secondString = #"bar";
NSString *thirdString = #"baz";
NSString *joinedString = [#[firstString, secondString, thirdString] join];
You can achieve it by adding the join method to NSArray with a category:
#import "NSArray+Join.h"
#implementation NSArray (Join)
-(NSString *)join
{
return [self componentsJoinedByString:#""];
}
#end
#[] it's the short definition for NSArray, I think this is the fastest method to concatenate strings.
If you don't want to use the category, use directly the componentsJoinedByString: method:
NSString *joinedString = [#[firstString, secondString, thirdString] componentsJoinedByString:#""];
You can use NSArray as
NSString *string1=#"This"
NSString *string2=#"is just"
NSString *string3=#"a test"
NSArray *myStrings = [[NSArray alloc] initWithObjects:string1, string2, string3,nil];
NSString *fullLengthString = [myStrings componentsJoinedByString:#" "];
or
you can use
NSString *imageFullName=[NSString stringWithFormat:#"%# %# %#.", string1,string2,string3];
Either of these formats work in XCode7 when I tested:
NSString *sTest1 = {#"This" " and that" " and one more"};
NSString *sTest2 = {
#"This"
" and that"
" and one more"
};
NSLog(#"\n%#\n\n%#",sTest1,sTest2);
For some reason, you only need the # operator character on the first string of the mix.
However, it doesn't work with variable insertion. For that, you can use this extremely simple solution with the exception of using a macro on "cat" instead of "and".
For all Objective C lovers that need this in a UI-Test:
-(void) clearTextField:(XCUIElement*) textField{
NSString* currentInput = (NSString*) textField.value;
NSMutableString* deleteString = [NSMutableString new];
for(int i = 0; i < currentInput.length; ++i) {
[deleteString appendString: [NSString stringWithFormat:#"%c", 8]];
}
[textField typeText:deleteString];
}
listOfCatalogIDs =[#[#"id[]=",listOfCatalogIDs] componentsJoinedByString:#""];
Let's imagine that u don't know how many strings there.
NSMutableArray *arrForStrings = [[NSMutableArray alloc] init];
for (int i=0; i<[allMyStrings count]; i++) {
NSString *str = [allMyStrings objectAtIndex:i];
[arrForStrings addObject:str];
}
NSString *readyString = [[arrForStrings mutableCopy] componentsJoinedByString:#", "];
Inspired by NSMutableString idea from Chris, I make a perfect macro imho.
It supports insert nil elements without any Exceptions.
#import <libextobjc/metamacros.h>
#define STR_CONCAT(...) \
({ \
__auto_type str__ = [NSMutableString string]; \
metamacro_foreach_cxt(never_use_immediately_str_concatify_,, str__, __VA_ARGS__) \
(NSString *)str__.copy; \
})
#define never_use_immediately_str_concatify_(INDEX, CONTEXT, VAR) \
[CONTEXT appendString:VAR ?: #""];
Example:
STR_CONCAT(#"button_bg_", #(count).stringValue, #".png");
// button_bg_2.png
If you like, you can use id type as parameter by using [VAR description] instead of NSString.