java 反转字符串数组中每个单词的Java方法
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Java method to reverse every word in an array of strings
提问by Justin
I'm trying to make a method that will take an array of strings and return an array with all the words in reverse order but my code is not working.
我正在尝试创建一个方法，该方法将采用一个字符串数组并以相反的顺序返回一个包含所有单词的数组，但我的代码不起作用。
When I run it i get "[Ljava.lang.String;@74122d9c"
当我运行它时，我得到“[Ljava.lang.String;@74122d9c”
Test case: String[]words={"Monday","Tuesday","Wednesday"}; -->{"yadnoM","yadsueT","yadsendeW"};
测试用例：String[]words={"Monday","Tuesday","Wednesday"}; -->{"yadnoM","yadsueT","yadsendeW"};
public String[] reverseString(String[] words)
{
String[] t=new String[words.length];
for(int i=0;i<words.length;i++)
{
for(int j=words[i].length()-1;j>=0;j--)
{
t[i]+=words[i].substring(j,j+1);
}
}
return t;
}
回答by Scary Wombat
try using StringBuilder.reverse
尝试使用 StringBuilder.reverse
public String[] reverseString(String[] words) {
String[] t = new String[words.length];
for (int i = 0; i < words.length; i++) {
t[i]= new StringBuilder(words[i]).reverse().toString();
}
return t;
}
Update
更新
The fact that you are getting When I run it i get "[Ljava.lang.String;@74122d9c"is beccase you are printing the whole String array as one [Ljava.lang.Stringmeans String array. You will need to iterate over the array to print out the Strings one-by-one
你得到的事实When I run it i get "[Ljava.lang.String;@74122d9c"是因为你正在打印整个 String 数组，因为它[Ljava.lang.String意味着 String 数组。您将需要遍历数组以一一打印出字符串
回答by Panther
You can transform your string into StringBuilder and it had reverse method. And its always better to use foreach rather than for, until there is actual need.
您可以将字符串转换为 StringBuilder 并且它具有反向方法。并且在实际需要之前使用 foreach 而不是 for 总是更好。
public String[] reverseString(String[] words) {
String[] t = new String[words.length];
for (String wordTemp : words) {
StringBuilder sb = new StringBuilder(wordTemp);
t[i] = sb.reverse().toString();
}
return t;
}
Alternate approach :-
替代方法：-
public String[] reverseString(String[] words)
{
String[] t=new String[words.length];
for(int i=0;i<words.length;i++)
{
//added for setting elemennt as emptyString instead of null
t[i] = "";
for(int j=words[i].length()-1;j>=0;j--)
{
t[i]+=words[i].substring(j,j+1);
}
}
//using loop
for(int i=0;i<words.length;i++)
{
System.out.println(t[i]);
}
//using Arrays Method
System.out.println(Arrays.toString(t));
return t;
}
回答by Shadow
When I run your code, I didn't get the same error that you posted, but I did notice that nullwas at the end of each reversed word.
当我运行您的代码时，我没有收到您发布的相同错误，但我确实注意到它null位于每个反向单词的末尾。
nullyadnoM
nullyadseuT
nullyadsendeW
Which is beacuse when you create a new string array, all it's values default to null:
这是因为当你创建一个新的字符串数组时，它的所有值默认为 null：
String[] t = new String[words.length];
The easiest way to fix it is to set it's value to an empty string, before you start adding to it:
修复它的最简单方法是在开始添加之前将其值设置为空字符串：
public static String[] reverseString(String[] words)
{
String[] t = new String[words.length];
for (int i = 0; i < words.length; i++)
{
t[i] = "";
for (int j = words[i].length() - 1; j >= 0; j--)
t[i] += words[i].charAt(j);
}
return t;
}
I have tested this code, and it works perfectly fine for me.
我已经测试了这段代码，它对我来说非常好。
To output the array, instead of using
输出数组，而不是使用
System.out.println(words);
use the following:
使用以下内容：
System.out.println(Arrays.toString(words));
This will give you the output:
这将为您提供输出：
[yadnoM, yadseuT, yadsendeW]
回答by Ravi Durairaj
Below Code is working fine with the help Stringbuilder reverse function.
下面的代码在帮助 Stringbuilder 反向功能下工作正常。
public class Example {
公共类示例{
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
String[] irreverseStr = {"Monday","Tuesday","Wendesday","Thursday","Friday","Saturday","Sunday"};
String[] reverseStr = new Example().getReverseArray(irreverseStr);
for(int j = 0; j < reverseStr.length; j++){
System.out.println(reverseStr[j]);
}
}
public String[] getReverseArray(String[] str){
String [] reversestr = new String[str.length];
for(int i=0;i<reversestr.length;i++){
reversestr[i] = new StringBuilder(str[i]).reverse().toString();
}
return reversestr;
}
}
}
回答by Shiva
Well, to return an array with all the words in reverse order try code below,
好吧，要以相反的顺序返回一个包含所有单词的数组，请尝试下面的代码，
import java.util.Arrays;
public class ArrayUtilsReverse
{
public static void main(String[] args)
{
String strArray[] = { "Monday","Tuesday","Wednesday" };
System.out.println("Print string array in reverse order java : " + Arrays.toString(strArray));
for(int a = 0; a < strArray.length / 2; a++)
{
String str = strArray[a];
strArray[a] = strArray[strArray.length - a - 1];
strArray[strArray.length - a - 1] = str;
}
System.out.println("Reversed array : ");
for(int a = 0; a < strArray.length; a++)
{
System.out.println(strArray[a]);
}
}
}
Output:
输出：
Print string array in reverse order java : [Monday, Tuesday, Wednesday]
Reversed array :
Wednesday
Tuesday
Monday
For more examples on reverse string array in java refer thisresource.
有关 Java 中反向字符串数组的更多示例，请参阅此资源。
回答by Ankur Singhal
public static void main(String[] args) {
String[] words = { "Monday", "Tuesday", "Wednesday" };
for (int i = 0 ; i < words.length ; i++) {
words[i] = Reverse(words[i]);
}
for (int i = 0 ; i < words.length ; i++) {
System.out.println(words[i]);
}
}
private static String Reverse(String str) {
StringBuilder result = new StringBuilder();
StringTokenizer st = new StringTokenizer(str, "");
while (st.hasMoreTokens()) {
StringBuilder thisToken = new StringBuilder(st.nextToken());
result.append(thisToken.reverse() + " ");
}
return result.toString();
}
Output
输出
yadnoM
yadseuT
yadsendeW
Also you can use org.apache.commons.lang3.StringUtils;, just to reduce your effort/shorten the code
你也可以使用org.apache.commons.lang3.StringUtils;，只是为了减少你的工作/缩短代码
private static String Reverse(String str) {
return StringUtils.reverse(str);
}
回答by Arun Xavier
public static String[] reverseString(String[] words) {
String[] t = new String[words.length];
for (int i = 0; i < words.length; i++) {
t[i]=new StringBuffer(words[i]).reverse().toString();
}
return t;
}
try StringBuffer's reverse method
试试 StringBuffer 的 reverse 方法
