我一直在使用从函数调用中返回的c#字符串[]数组。我可以强制转换为Generic集合,但我想知道是否有更好的方法,可能是使用临时数组。
从c#数组中删除重复项的最佳方法是什么?
我一直在使用从函数调用中返回的c#字符串[]数组。我可以强制转换为Generic集合,但我想知道是否有更好的方法,可能是使用临时数组。
从c#数组中删除重复项的最佳方法是什么?
当前回答
在下面找到答案。
class Program
{
static void Main(string[] args)
{
var nums = new int[] { 1, 4, 3, 3, 3, 5, 5, 7, 7, 7, 7, 9, 9, 9 };
var result = removeDuplicates(nums);
foreach (var item in result)
{
Console.WriteLine(item);
}
}
static int[] removeDuplicates(int[] nums)
{
nums = nums.ToList().OrderBy(c => c).ToArray();
int j = 1;
int i = 0;
int stop = 0;
while (j < nums.Length)
{
if (nums[i] != nums[j])
{
nums[i + 1] = nums[j];
stop = i + 2;
i++;
}
j++;
}
nums = nums.Take(stop).ToArray();
return nums;
}
}
这是基于我刚刚解决的一个测试的一点贡献,可能对这里其他顶级贡献者的改进有所帮助。 以下是我所做的事情:
I used OrderBy which allows me order or sort the items from smallest to the highest using LINQ I then convert it to back to an array and then re-assign it back to the primary datasource So i then initialize j which is my right hand side of the array to be 1 and i which is my left hand side of the array to be 0, i also initialize where i would i to stop to be 0. I used a while loop to increment through the array by going from one position to the other left to right, for each increment the stop position is the current value of i + 2 which i will use later to truncate the duplicates from the array. I then increment by moving from left to right from the if statement and from right to right outside of the if statement until i iterate through the entire values of the array. I then pick from the first element to the stop position which becomes the last i index plus 2. that way i am able to remove all the duplicate items from the int array. which is then reassigned.
其他回答
在下面找到答案。
class Program
{
static void Main(string[] args)
{
var nums = new int[] { 1, 4, 3, 3, 3, 5, 5, 7, 7, 7, 7, 9, 9, 9 };
var result = removeDuplicates(nums);
foreach (var item in result)
{
Console.WriteLine(item);
}
}
static int[] removeDuplicates(int[] nums)
{
nums = nums.ToList().OrderBy(c => c).ToArray();
int j = 1;
int i = 0;
int stop = 0;
while (j < nums.Length)
{
if (nums[i] != nums[j])
{
nums[i + 1] = nums[j];
stop = i + 2;
i++;
}
j++;
}
nums = nums.Take(stop).ToArray();
return nums;
}
}
这是基于我刚刚解决的一个测试的一点贡献,可能对这里其他顶级贡献者的改进有所帮助。 以下是我所做的事情:
I used OrderBy which allows me order or sort the items from smallest to the highest using LINQ I then convert it to back to an array and then re-assign it back to the primary datasource So i then initialize j which is my right hand side of the array to be 1 and i which is my left hand side of the array to be 0, i also initialize where i would i to stop to be 0. I used a while loop to increment through the array by going from one position to the other left to right, for each increment the stop position is the current value of i + 2 which i will use later to truncate the duplicates from the array. I then increment by moving from left to right from the if statement and from right to right outside of the if statement until i iterate through the entire values of the array. I then pick from the first element to the stop position which becomes the last i index plus 2. that way i am able to remove all the duplicate items from the int array. which is then reassigned.
public static int RemoveDuplicates(ref int[] array)
{
int size = array.Length;
// if 0 or 1, return 0 or 1:
if (size < 2) {
return size;
}
int current = 0;
for (int candidate = 1; candidate < size; ++candidate) {
if (array[current] != array[candidate]) {
array[++current] = array[candidate];
}
}
// index to count conversion:
return ++current;
}
测试了下面的&它工作。最酷的是,它还做了一个文化敏感搜索
class RemoveDuplicatesInString
{
public static String RemoveDups(String origString)
{
String outString = null;
int readIndex = 0;
CompareInfo ci = CultureInfo.CurrentCulture.CompareInfo;
if(String.IsNullOrEmpty(origString))
{
return outString;
}
foreach (var ch in origString)
{
if (readIndex == 0)
{
outString = String.Concat(ch);
readIndex++;
continue;
}
if (ci.IndexOf(origString, ch.ToString().ToLower(), 0, readIndex) == -1)
{
//Unique char as this char wasn't found earlier.
outString = String.Concat(outString, ch);
}
readIndex++;
}
return outString;
}
static void Main(string[] args)
{
String inputString = "aAbcefc";
String outputString;
outputString = RemoveDups(inputString);
Console.WriteLine(outputString);
}
}
--AptSenSDET
下面这段代码试图从ArrayList中删除重复项,尽管这不是最佳解决方案。在一次面试中,我被问到通过递归删除重复项,而不使用第二个/temp数组列表:
private void RemoveDuplicate()
{
ArrayList dataArray = new ArrayList(5);
dataArray.Add("1");
dataArray.Add("1");
dataArray.Add("6");
dataArray.Add("6");
dataArray.Add("6");
dataArray.Add("3");
dataArray.Add("6");
dataArray.Add("4");
dataArray.Add("5");
dataArray.Add("4");
dataArray.Add("1");
dataArray.Sort();
GetDistinctArrayList(dataArray, 0);
}
private void GetDistinctArrayList(ArrayList arr, int idx)
{
int count = 0;
if (idx >= arr.Count) return;
string val = arr[idx].ToString();
foreach (String s in arr)
{
if (s.Equals(arr[idx]))
{
count++;
}
}
if (count > 1)
{
arr.Remove(val);
GetDistinctArrayList(arr, idx);
}
else
{
idx += 1;
GetDistinctArrayList(arr, idx);
}
}
下面是HashSet<string>方法:
public static string[] RemoveDuplicates(string[] s)
{
HashSet<string> set = new HashSet<string>(s);
string[] result = new string[set.Count];
set.CopyTo(result);
return result;
}
不幸的是,这个解决方案也需要。net框架3.5或更高版本,因为HashSet直到该版本才被添加。你也可以使用array.Distinct(),这是LINQ的一个特性。