objective c - stringByAppendingString on same object -

-

I have a question on NSString , so the question is:

< Pre> NSString str = @ "Hello"; Str = [str stringByAppendingString: @ "world"];

If we get NSLog to str we will get an output - HelloWorld

So my question is that if str is NSString class variable one can not be changed after its one constant (which has been defined) ) So how can we change it, (note that I have used the same NSString object str ).

You have not declared the string as static, but NSString It is irreversible that you are creating a new string and replacing str is an unstable type in many OBJ-C classes, so if you want to modify this string as an example, So you want something else: 

  NSMutableString * str = [NSMutableString stringWithString: @ "Hello"]; [Stradded string: @ "world"];

Note, @ "Hello" is a NSString , so by trying to start a NSMutableString using that syntax An error will occur


Comments

Post a Comment

Popular posts from this blog

java - org.apache.http.ProtocolException: Target host is not specified -

-
I have written a simple httprequest / response code and I am getting this error below: I used to type in my classpath httpclient, httpcore, common -Codecs and general logging. I am very new to Java and I do not know what's going on here. Please help me. code: import org.apache.http.client.HttpClient; Import org.apache.http.client.methods.HttpGet; Import org.apache.http.HttpResponse; Import org.apache.http.impl.client.HttpClientBuilder; Import org.apache.http.Header; Import org.apache.http.HttpHeaders; Public class UnshorteningUrl {public static zero main (string [] args throws exception {HttpGet request = zero; HTTP Client Client = HTTP ClientBuilder.credit (). Build (); Try {Request = New HTTP Gate ("trib.me/1lBFzSi"); HttpResponse httpResponse = client.execute (request); Header [] header = httpResponse.getHeaders (HttpHeaders.LOCATION); // Preconditions.checkState (headers.length == 1); String new url = header [0] .getValue (); System.out.println ("new url...
Read more

c# - Chart control: Design messed Up after clearing and re-adding Y-Values -

-
Image
The day was struggling with this. I have three series on a chart that looks like this. Note: I am using vanof control. They are being added on the basis of input from the calculation. I am using this code to add value to each series. this.chart1.Series ["green"]. Points. AddY (greenvalue); This.chart1.Series ["totalsaving"] Points.AddY (totalsavingvalue). This.chart1.Series ["blue"] Points.AddY (bluevalue). I have set series properties like this. Both green and totalsaving are set to StackedColumn, the blue chart is set to the column for type. I started then To do is a button that brings the user back to the input field and then I am using this code to clear the series values ​​on the start code. chart 1. Series ["totaling"]. Points. clear (); Chart1.Series ["green"] Points.Clear () .; Chart1.Series ["blue"] Points.Clear () .; The same calculation click above is being calculated for the calculation of th...
Read more

api - Google Analytics with CakePHP -

-
I am trying to get data from my Google analytic account, I have been using a plugin for KPHP and its I am The plugin works, I can get a list of books from a specific author like the example. I want to display some information for cake from my Google Analytical Account. I have a few questions, how can I get Project_ID, IDs, secret? CorePPP of my plugin: $ Config = array ('GoogleAPI' => defines the option of array (/ ** * 'client' client) / 'Client' = & gt; array ('ApplicationName' = & gt; 'app', 'id' = & gt; '?', 'Secret' = & gt; '?', 'Developer key' & Gt; 'xxxxxxxxxxxxxxxxxxxx'),)); Test Controller: & lt ;? Php AP :: Usage ('app controller', 'controller'); Class Test Controller AppController {Public $ component = array ('GoogleAPI.GoogleAPI' => Array ('service' => array ('analytics')); Public function index...
Read more