Java 按字母顺序对字符串中的字符进行排序
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Sorting characters alphabetically in a String
提问by
Could smb please explaing the process of sorting characters of Stringalphabetically? For example, if I have String "hello"the output should be "ehllo"but my code is doing it wrong.
请smb解释一下String按字母顺序排列字符的过程吗？例如，如果我有String "hello"输出应该是"ehllo"但我的代码做错了。
public static void main(String[] args)
{
String result = "";
Scanner kbd = new Scanner(System.in);
String input = kbd.nextLine();
for(int i = 1; i < input.length(); i++)
{
if(input.charAt(i-1) < input.charAt(i))
result += input.charAt(i-1);
//else
// result += input.charAt(i);
}
System.out.println(result);
}
}
采纳答案by Razib
You may do the following thing -
你可以做以下事情——
1.Convert your String to char[]array.
2.Using Arrays.sort()sort your char array
1.将您的字符串转换为char[]数组。
2.使用Arrays.sort()排序你的字符数组
Code snippet:
代码片段：
String input = "hello";
char[] charArray = input.toCharArray();
Arrays.sort(charArray);
String sortedString = new String(charArray);
System.out.println(sortedString);
Or if you want to sort the array using for loop (for learning purpose) you may use (But I think the first one is best option ) the following code snippet-
或者，如果您想使用 for 循环（出于学习目的）对数组进行排序，您可以使用（但我认为第一个是最好的选择）以下代码片段-
input="hello";
char[] charArray = input.toCharArray();
length = charArray.length();
for(int i=0;i<length;i++){
for(int j=i+1;j<length;j++){
if (charArray[j] < charArray[i]) {
char temp = charArray[i];
charArray[i]=arr[j];
charArray[j]=temp;
}
}
}
回答by fsalazar_sch
In your for bucle is starting at 1, should be start at zero
在你的 for bucle 从 1 开始，应该从零开始
for(int i = 0; i < input.length(); i++){...}
回答by GreySage
Sorting as a task has a lower bound of O(n*logn), with n being the number of elements to sort. What this means is that if you are using a single loop with simple operations, it will not be guaranteed to sort correctly.
A key element in sorting is deciding what you are sorting by. In this case its alphabetically, which, if you convert each character to a char, equates to sorting in ascending order, since a char is actually just a number that the machine maps to the character, with 'a' < 'b'. The only gotcha to look out for is mixed case, since 'z' < 'A'. To get around, this, you can use str.tolower(). I'd recommend you look up some basic sorting algorithms too.
作为任务排序的下限为 O(n*logn)，n 是要排序的元素数。这意味着如果您使用具有简单操作的单个循环，则不能保证正确排序。排序中的一个关键要素是决定您排序的依据。在这种情况下，它按字母顺序排列，如果将每个字符转换为字符，则相当于按升序排序，因为字符实际上只是机器映射到字符的数字，其中 'a' < 'b'。唯一需要注意的问题是大小写混合，因为 'z' < 'A'。为了解决这个问题，您可以使用str.tolower(). 我建议您也查找一些基本的排序算法。
回答by rashedcs
Procedure :
程序 ：
At first convert the string to char array
Then sort the array of character
Convert the character array to string
Print the string
首先将字符串转换为字符数组
然后对字符数组进行排序
将字符数组转换为字符串
打印字符串
Code snippet:
代码片段：
String input = "world";
char[] arr = input.toCharArray();
Arrays.sort(arr);
String sorted = new String(arr);
System.out.println(sorted);
回答by bpjoshi
You can sort a String in Java 8 using Stream as below:
您可以使用 Stream 对 Java 8 中的字符串进行排序，如下所示：
String sortedString =
Stream.of("hello".split(""))
.sorted()
.collect(Collectors.joining());
回答by bpjoshi
You can do this using Arrays.sort, if you put the characters into an array first.
Arrays.sort如果先将字符放入数组，则可以使用,来执行此操作。
Character[] chars = new Character[str.length()];
for (int i = 0; i < chars.length; i++)
chars[i] = str.charAt(i);
// sort the array
Arrays.sort(chars, new Comparator<Character>() {
public int compare(Character c1, Character c2) {
int cmp = Character.compare(
Character.toLowerCase(c1.charValue()),
Character.toLowerCase(c2.charValue())
);
if (cmp != 0) return cmp;
return Character.compare(c1.charValue(), c2.charValue());
}
});
Now build a string from it using StringBuilder.
现在使用StringBuilder.
回答by bpjoshi
Most basic and brute force approach using the two for loop: It sort the string but with the cost of O(n^2) time complexity.
使用两个 for 循环的最基本和蛮力方法：它对字符串进行排序，但时间复杂度为 O(n^2)。
public void stringSort(String str){
char[] token = str.toCharArray();
for(int i = 0; i<token.length; i++){
for(int j = i+1; j<token.length; j++){
if(token[i] > token[j]){
char temp = token[i];
token[i] = token[j];
token[j] = temp;
}
}
}
System.out.print(Arrays.toString(token));
}
回答by Tarun Jadhav
public class SortCharcterInString {
公共类 SortCharcterInString {
public static void main(String[] args) {
String str = "Hello World";
char[] arr;
List<Character> L = new ArrayList<Character>();
for (int i = 0; i < str.length(); i++) {
arr = str.toLowerCase().toCharArray();
L.add(arr[i]);
}
Collections.sort(L);
str = L.toString();
str = str.replaceAll("\[", "").replaceAll("\]", "")
.replaceAll("[,]", "").replaceAll(" ", "");
System.out.println(str);
}
