NSMutableString check last and second last character - iphone

I have a NSMutableString. I need to check whether the last character is #":" or last two characters are #": "
How to do that?


Use the hasSuffix: method of NSString.


Identifies last char:
NSString *lastChar = [yourstr substringFromIndex: [yourstr length] - 1];
Identifies last two chars:
NSString *lastTwoChar = [yourstr substringFromIndex: [yourstr length] - 2];

Related

Replace a character in a String iPhone

I want to replace a single character at a particular position in a string.
Example
String: 123-456-7890
Desired Output: 123-406-7890 (Replacing 5 at fifth position with 0)

https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSString_Class/
visit here and read all about string

Use stringByReplacingCharactersInRange:withString:, forming the NSRange variable to indicate the 5th position.
NSString *phoneNumber = #"123-456-7890";
NSString *newString = [phoneNumber stringByReplacingCharactersInRange:NSMakeRange(5, 1) withString:#"0"];
NSLog(#"%#", newString);
Output: 123-406-7890
Read all about NSString.

for replacing string there are lots of way:
NSString *str = [yourString stringByReplacingOccuranceOfString:#"5" withString:#"0"];
second way first get range of string like:
NSRange range = [yourSting rangeOfString:#"5"];
NSString *first = [yourString substringToIndex:range.location];
NSString *second = [yourString substringFromIndex:range.location+range.length];
NSString *yourNewStr = [NSString stringWithFormat:#"%#0%#",first,second];
Tere are lots of other using string operation but First one is best in that.

Get the range (i.e. index) of first occurrence of the substring.
Then replace at that range with your desired replace value.
NSString *originalString = #"123 456 789";
NSRange r = [originalString rangeOfString:#"5"];
NSString *newString = [originalString stringByReplacingCharactersInRange:r withString:#"0"];

If you want to actually replace the 5th character rather than just any 5 you need to make a range first.
NSRange range = NSMakeRange(5, 1);
NSString *newString = [initialString stringByReplacingCharactersInRange:range withString:#"0"];
Edit: Corrected make range length

you can use :-
NSString *replacechar = #"0";
NSString *newString= [String stringByReplacingCharactersInRange:NSMakeRange(5,1) withString:replacechar];

How do I remove the end of an NSMutableString?

I have the following NSMutableString:
#"1*2*3*4*5"
I want to find the first * and remove everything after it, so my string = #"1"; How do I do this?

NSMutableString *string = [NSMutableString stringWithString:#"1*2*3*4*5"];
NSRange range = [string rangeOfString:#"*"];
if (range.location != NSNotFound)
{
[string deleteCharactersInRange:NSMakeRange(range.location, [string length] - range.location)];
}

You could try to divide this string by a separator and get the first object
NSString *result = [[MyString componentsSeparatedByString:#"*"]objectAtIndex:0];
After calling componentsSeparatedByString:#"*" you'll get the array of strings, separated by *,and the first object is right what you need.

Here's yet another strategy, using the very flexible NSScanner.
NSString* beginning;
NSScanner* scanner = [NSScanner scannerWithString:#"1*2*3*4*5"];
[scanner scanUpToString:#"*" intoString:&beginning];

You could use -rangeOfString: to find the index of the first asterisk and use that with -substringToIndex: to extract a substring from the original input. Something like this perhaps...
NSMutableString *input = #"1*2*3*4*5";
// Finds the range of the first instance. See NSString docs for more options.
NSRange firstAsteriskRange = [input rangeOfString:#"*"];
NSString *trimmedString = [input substringToIndex:firstAsteriskRange.location + 1];

How to check whether a string contains white spaces

How to check whether a string contains whitespaces in between characters?

use rangeOfCharactersFromSet:
NSString *foo = #"HALLO WELT";
NSRange whiteSpaceRange = [foo rangeOfCharacterFromSet:[NSCharacterSet whitespaceCharacterSet]];
if (whiteSpaceRange.location != NSNotFound) {
NSLog(#"Found whitespace");
}
note: this will also find whitespace at the beginning or end of the string. If you don't want this trim the string first...
NSString *trimmedString = [foo stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
NSRange whiteSpaceRange = [trimmedString rangeOfCharacterFromSet:[NSCharacterSet whitespaceCharacterSet]];

You can also follow these steps:
NSArray *componentsSeparatedByWhiteSpace = [testString componentsSeparatedByString:#" "];
If there is any whitespace in your string, then it will separate those and store different components in the array. Now you need to take the count of array. If count is greater than 1, it means there are two components, i.e, presence of white space.
if([componentsSeparatedByWhiteSpace count] > 1){
NSLog(#"Found whitespace");
}

Check NSMakeRange is Able to take range or Not

I am currently using the below code to take the substring
NSString *s1 = [stringName substringWithRange: NSMakeRange(0, 2)];
NSString *s2 = [stringName substringWithRange: NSMakeRange(2, 4)];
NSString *s3 = [stringName substringWithRange: NSMakeRange(6, [stringName length])];
Here, how to check the range is valid or not because i am not able to length of string to validate because it may differ on time. Please help me in this issue..

For s3, you're starting at position and ask for exactly as many characters as there are in the string. But since you're starting at position 6, you're asking for 6 characters too many. You need to do:
NSString *s3 = [stringName substringWithRange: NSMakeRange(6, [stringName length] - 6)];

As the apple documentation says ..
substringWithRange:
Returns a string object containing the characters of the receiver that lie within a given range.
- (NSString *)substringWithRange:(NSRange)aRange
aRange
A range. The range must not exceed the bounds of the receiver.
You need to check every time when you construct an NSMakeRange(), whether the Range you specified within the length of your String OR not ... by Using some if and else condition

Remove newline character from first line of NSString

How can I remove the first \n character from an NSString?
Edit: Just to clarify, what I would like to do is:
If the first line of the string contains a \n character, delete it else do nothing.
ie: If the string is like this:
#"\nhello, this is the first line\nthis is the second line"
and opposed to a string that does not contain a newline in the first line:
#"hello, this is the first line\nthis is the second line."
I hope that makes it more clear.

[string stringByTrimmingCharactersInSet:[NSCharacterSet newlineCharacterSet]]
will trim your string from any kind of newlines, if that's what you want.
[string stringByReplacingOccurrencesOfString:#"\n" withString:#"" options:0 range:NSMakeRange(0, 1)]
will do exactly what you ask and remove newline if it's the first character in the string

This should do the trick:
NSString * ReplaceFirstNewLine(NSString * original)
{
NSMutableString * newString = [NSMutableString stringWithString:original];
NSRange foundRange = [original rangeOfString:#"\n"];
if (foundRange.location != NSNotFound)
{
[newString replaceCharactersInRange:foundRange
withString:#""];
}
return [[newString retain] autorelease];
}

Rather than creating an NSMutableString and using a few retain/release calls, you can use only the original string and simplify the code by using the following instead: (requires 10.5+)
NSRange foundRange = [original rangeOfString:#"\n"];
if (foundRange.location != NSNotFound)
[original stringByReplacingOccurrencesOfString:#"\n"
withString:#""
options:0
range:foundRange];
(See -stringByReplacingOccurrencesOfString:withString:options:range: for details.)
The result of the last call method call can even be safely assigned back to original IF you autorelease what's there first so you don't leak the memory.