Check for an empty string

I have a little question. Seems easy but I don't get it worki开发者_StackOverflow社区ng. All I want is check if a string is empty or not. Here's what I have so far:

if(mystring.text != @""){
    myPath = [myPath stringByAppendingString:mystring.text];
}

To compare an NSString to another one, you would use isEqualToString. You're checking for inequality, so it would be:

NSString *text = ...;

if (![text isEqualToString:@""]) {
    ...
}

But really, since you're just checking if the string is empty, you'll want something like

NSString *text = ...;

if ([text length] != 0) {
    ...
}

Note that if text is nil, the code in the if-statement will not execute. This is because [nil length] will return 0. For more information about that, see "Sending Messages to nil" in Apple's documentation.

I suspect mystring.text is an NSString in your case, so it would be

if ([mystring.text length] != 0) {
    myPath = [myPath stringByAppendingString:mystring.text];
}

you can try below few lines of code:

NSString *trimedString = [someString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];


if(trimedstr != [NSNull null]&& ![trimedstr isEqualToString:@""])
{
    if([trimedstr length]>0)
    {
        NSLog(@"%@", trimedstr);
    }
    else
     NSLog(@"%@",@"this is empty string");
}

I usually check if the length is > 0 for a positive test case, which also handles if nil.

something like: if ([someString length] > 0) { // do something with someString }

I'd use something like:

if(someString && [someString lenght])
    // string is not empty