NSString 过滤首尾空白、空行，把多换行转为单换行

- (NSString *)filterBlankAndBlankLines:(NSString *)str

{

NSMutableString *Mstr = [NSMutableString
string];

NSArray *arr = [str
componentsSeparatedByString:@"\n"];

for (int i =
0; i < arr.count; i++) {

NSString *tempStr = (NSString *)arr[i];

[tempStr stringByTrimmingCharactersInSet:[NSCharacterSet
whitespaceAndNewlineCharacterSet]]; //去除掉首尾的空白字符和换行字符

[tempStr stringByReplacingOccurrencesOfString:@"\r"
withString:@""];

[tempStr stringByReplacingOccurrencesOfString:@"\n"
withString:@""];

if (tempStr.length !=
0) {

[Mstr appendString:arr[i]];

if (i < [arr count] -
1) {

[Mstr appendString:@"\n"];

}

}

}

return Mstr;

}

NSString 过滤首尾空白、空行，把多换行转为单换行