拷贝字符串中指定数据-源代码

//拷贝字符串中的指定数据
//SourceData 元数据
//FirstPlaceIndex 拷贝起始位置编号
//LastPlaceIndex  拷贝结束位置编号
-(NSString *)CopyPartTextToString : (NSString *)SourceData
  FirstPlaceIndex : (NSInteger)FirstPlaceIndex
  LastPlaceIndex : (NSInteger) LastPlaceIndex;

---

.m

-(NSString *)CopyPartTextToString : (NSString *)SourceData
  FirstPlaceIndex : (NSInteger)FirstPlaceIndex
  LastPlaceIndex : (NSInteger) LastPlaceIndex{
if (FirstPlaceIndex < 1) FirstPlaceIndex = 1;
if (LastPlaceIndex > [SourceData length])LastPlaceIndex = [SourceData length];
if (FirstPlaceIndex > LastPlaceIndex) returnnil;

NSRange iRange;
iRange.location = FirstPlaceIndex - 1;
iRange.length = LastPlaceIndex - FirstPlaceIndex + 1;

NSString *AData = [SourceData substringWithRange:iRange];
NSString *ReturnValue = [[NSString alloc]initWithString:AData];
[AData release];

return ReturnValue;
}