Can I copy from NSString to NSMutableString?

Question

I have strValue as NSString , and I'd like to copy strValue 's content to another place.

The place is mstrValue , which is an NSMutableString . Space for mstrValue has already been allocated.

I wonder how can I use memcpy or strcpy for this purpose.

If it is impossible, I'd like to know other ways to do it.

Answer 1

Your question isn't too clear but if you want to set the mutable string's value to the other string then do this:

[mstrValue setString:strValue];

If you want to append the value then do this:

[mstrValue appendString:strValue];

Both of these assume that at some point you did:

mstrValue = [[NSMutableString alloc] init];

Have a look at the docs for NSMutableString . There are lots of methods for updating its value.

Answer 2

I'll always prefer to used [NSString stringWithFormat@"%@", strValue]; because then you clearly get a new autoreleased string and can dispose of string "strValue" correctly.

NSMutableString *mstrValue = [NSMutableString stringWithFormat:@"%@", strValue];

OR

NSMutableString *mstrValue = [NSMutableString stringWithString:strValue];

Answer 3

除非要正确处理字符串编码，否则应避免使用memcpy或strcpy。

Answer 4

Yes with object allocation:

NSMutableString *mstrValue = [[NSMutableString alloc] initWithString:strValue];

You can do it.