NSString trim \ n

Question

我在字符串中有多个换行符。但是如果在字符串的开头或结尾处找到它，我只希望它被修剪。如果在它们之间发现则很好。怎么做？

Answer 1

您需要使用：

- (NSString *)stringByReplacingOccurrencesOfString:(NSString *)target withString:(NSString *)replacement options:(NSStringCompareOptions)options range:(NSRange)searchRange;

目标将为@"\n"

替换将为@""

范围将是：

NSMakeRange(0,2); // for the beginning

和

NSMakeRange(string.length-2,2); // to the end

例如 -

//for the start
[yourString stringByReplacingOccurrencesOfString:@"\n" withString:@"" options:NSCaseInsensitiveSearch range:NSMakeRange(0,2)];

//for the end
[yourString stringByReplacingOccurrencesOfString:@"\n" withString:@"" options:NSCaseInsensitiveSearch range:NSMakeRange(yourString.length,2)];

您可以指定更长的范围，以确保它采用\ n。

Answer 2

NSString* str = @"hdskfh   dsakjfh akhf kasdhfk asdfkjash fkadshf1234        ";
NSRange rng = [str rangeOfCharacterFromSet: [NSCharacterSet characterSetWithCharactersInString: [str stringByReplacingOccurrencesOfString: @" " withString: @""]] options: NSBackwardsSearch];
str = [str substringToIndex: rng.location+1];

Answer 3

使用以下代码从开头和结尾删除\ n

NSString *str = @"\n test test \n test \n";

int firstOccurance = [str rangeOfString:@"\n"].location;
if (firstOccurance == 0) {
    str = [str substringFromIndex:1];
}

int lastOccurance = [str rangeOfString:@"\n" options:NSBackwardsSearch].location;
if (lastOccurance == str.length - 1) {
    str = [str substringToIndex:str.length - 2];
}

Answer 4

您可以尝试使用hasPrefix和hasSuffix

例如

NSString *str = @"\n This is a \n test \n";

if ([str hasPrefix:@"\n"])
{
     //remove it
}

if ([str hasSuffix:@"\n"])
{
      //remove it
}

Answer 5

您可以使用stringByTrimmingCharactersInSet修剪字符串两端的空格。

NSString* str = [myString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];