Add backslash to String in Objective-c

Question

I have a problem identical to this problem here.

I even want to encode the same infromation as him (it's a date/time for asp.net)...

When ever I try to add a backslash i get two backslashes since I used \.

Everyone in the thread above has claimed that this is a problem with NSLog and that NSString does treat \\ as a \. I have checked this further by using a packet sniffer to examine the packets I'm sending to the webserver and I can confirm that it is transmitting a double backslash instead of a single backslash.

Does anyone know how to add a backslash to a NSString?

Solution 1

The strings and NSLog are working fine for me:

NSLog(@"\\"); // output is one backslash
NSLog(@"\\\\"); // output is two backslashes
NSLog(@"\\/Date(100034234)\\/"); // output is \/Date(100034234)\/

What am I missing?

Solution 2

Try this:

yourStr =  [yourStr stringByReplacingOccurrencesOfString:@"\\\\" withString:@"\\"];
NSLog(@"%@", yourStr);

I had the same problem, turned out that my JSON Parser replaced all occurrances of "\\" with "\\\\", so when I NSLogged my original code like this:

NSString *jsonString = [myJSONStuff JSONRepresentation];
NSLog(@"%@", jsonString);

This is what I got:

{TimeStamp : "\\/Date(12345678)\\/"}

However, the string itself contained FOUR backslashes (but only 2 of them are printed by NSLog).

This is what helped me:

NSString *jsonString = [myJSONStuff JSONRepresentation];
jsonString = [jsonString stringByReplacingOccurrencesOfString:@"\\\\" withString:@"\\"];
NSLog(@"%@", jsonString);

The result:

{TimeStamp : "\/Date(12345678)\/"}

Comments

[Craig Warren]

Hi Gerry, Have you tried it? NSLog(@"\\/Date(1234534534)\\/"); outputs a double backslash for me. More importantly when i transmit that string over http the double backslash appears in the packet

[gerry3]

It works for me (I copied the exact code from your comment). I am running iPhone SDK 3.1.2 and Xcode 3.2.1.

[Costique]

On my machine NSLog(@"\\ %@", [NSString stringWithFormat: @"\\n \\\\t"]) correctly outputs "\ \n \\t"

[Craig Warren]

Gerry, I am using iPhone SDK 3.1.2 and XCode 3.1.4. The only difference in what I do is that I am saving my string to a pointer before displaying: NSString* dateString = [NSString stringWithFormat:@"\\/Date(%ld +0000)\\/", (long)temp*1000]; But I definetly get two backslashes

[gerry3]

That code also works fine for me. I set temp to 2331 and the output was: \/Date(2331000 +0000)\/

[Craig Warren]

Looks like it's something to do with the JSON parser I'm using... Oh Well thanks for your help. Always good to be challanged by someone until you realize you are wrong

[gerry3]

No problem. I use TouchJSON, but I haven't tested it with escaped backslashes. I am pretty sure the guy that recommended it to me used ASP.NET on his web server.

[Muhammad Yusuf]

This case happened to me too when converting from NSDictionary that contains NSString objects with backslashes in it to an NSString.