Java 获取字符串中每个单词的第一个字符
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Get the first character of each word in a String
提问by farhana konka
I am trying to get a program working which does the following:
我正在尝试让一个程序运行，它执行以下操作：
Let's say we have a Stringcalled name, set to "Stack Overflow Exchange". I want to output to the user "SOE", with the first characters of each word. I tried with the split()method, but I failed to do it.
假设我们有一个String被调用的name，设置为"Stack Overflow Exchange"。我想输出给 user "SOE"，每个单词的第一个字符。我尝试了该split()方法，但没有成功。
My code:
我的代码：
public class q4 {
public static void main(String args[]) {
String x = "michele jones";
String[] myName = x.split("");
for(int i = 0; i < myName.length; i++) {
if(myName[i] == "") {
String s = myName[i];
System.out.println(s);
}
}
}
}
I am trying to detect if there are any spaces, then I can simply take the next index. Could anyone tell me what I am doing wrong?
我试图检测是否有任何空格，然后我可以简单地取下一个索引。谁能告诉我我做错了什么？
采纳答案by brso05
Try splitting by " "(space), then getting the charAt(0)(first character) of each word and printing it like this:
尝试按" "（空格）分割，然后获取charAt(0)每个单词的（第一个字符）并像这样打印：
public static void main(String args[]) {
String x = "Shojibur rahman";
String[] myName = x.split(" ");
for (int i = 0; i < myName.length; i++) {
String s = myName[i];
System.out.println(s.charAt(0));
}
}
回答by Simone Gianni
String initials = "";
for (String s : fullname.split(" ")) {
initials+=s.charAt(0);
}
System.out.println(initials);
This works this way :
这是这样工作的：
- Declare a variable "initials" to hold the result
- Split the fullname string on space, and iterate on the single words
- Add to initials the first character of each word
- 声明一个变量“initials”来保存结果
- 在空格上拆分全名字符串，并迭代单个单词
- 将每个单词的第一个字符添加到首字母
EDIT :
编辑 ：
As suggested, string concatenation is often not efficient, and StringBuilder is a better alternative if you are working on very long strings :
正如所建议的那样，字符串连接通常效率不高，如果您正在处理很长的字符串，则 StringBuilder 是更好的选择：
StringBuilder initials = new StringBuilder();
for (String s : fullname.split(" ")) {
initials.append(s.charAt(0));
}
System.out.println(initials.toString());
EDIT :
编辑 ：
You can obtain a String as an array of characters simply :
您可以简单地将字符串作为字符数组获取：
char[] characters = initials.toString().toCharArray();
回答by StackFlowed
You need to spilt it with a space you cannot split with "". It doesn't mean anything. Another thing you did wrong was === in string comparison that is not correct. Please refer to How do I compare strings in Java?
你需要用一个你不能用“”分割的空间来溢出它。这不代表什么。你做错的另一件事是在字符串比较中 === 不正确。请参阅如何比较 Java 中的字符串？
public class q4 {
public static void main(String args[])
{
String x="Shojibur rahman";
String [] myName=x.split(" ");
for(int i=0; i<myName.length; i++)
{
if(!myName[i].equals(""))
{
System.out.println(myName[i]);
}
}
}
}
回答by Jesper
There are a number of errors in your code:
您的代码中有许多错误：
String [] myName=x.split("");
Did you really want to split on ""(empty string)? You probably wanted to split on spaces:
你真的想拆分""（空字符串）吗？您可能想在空格上拆分：
String [] myName=x.split(" ");
And:
和：
if(myName[i]=="")
Never compare strings with ==in Java, always use .equals:
永远不要将字符串与==Java 中的字符串进行比较，始终使用.equals：
if (myName[i].equals(""))
回答by Tim B
You are splitting on an empty string not a space " ". Your loops don't really make much sense either, I'm not sure what you are trying to do.
您正在拆分空字符串而不是空格“”。您的循环也没有多大意义，我不确定您要做什么。
String [] myName=x.split(" ");
for(int i=0; i<myName.length; i++)
{
if (!myName[i].isEmpty()) {
System.out.println(myName[i].charAt(0));
}
}
回答by Jake Huang
Since you don't have thread-safe with your program, you could use StringBuilder.
For the long string, i recommand you could use StringTokenizer.
由于您的程序没有线程安全，因此您可以使用StringBuilder. 对于长字符串，我建议您可以使用StringTokenizer.
回答by Jeffrey Bosboom
With Java 8 streams:
使用 Java 8 流：
String initials = Arrays.stream(str.split(" "))
.map(s -> s.substring(0, 1))
.collect(Collectors.joining());
System.out.println(initials);
回答by Marco Tulio Avila Cerón
The accepted reply in Java 8:
Java 8 中接受的回复：
/**
* Gets the first character of every word in the sentence.
*
* @param string
* @return
*/
public static String getFirstLetterFromEachWordInSentence(final String string) {
if (string == null) {
return null;
}
StringBuilder sb = new StringBuilder();
Arrays.asList(string.split(" ")).forEach(s -> sb.append(s.charAt(0)).append(" "));
return sb.toString().trim();
}
回答by Prashant Jajal
If you are using kotlin then you can use below code for get initial charactor
如果您使用的是 kotlin，则可以使用以下代码获取初始字符
val myName = name.split(" ")
val initial = myName.fold("", { acc, s -> acc + s[0] })
print(initial)
回答by Lokesh
Surprised that nobody mentioned about making use of an already available library. One can use here WordUtilsform apache commons-text
令人惊讶的是，没有人提到使用已经可用的库。可以在这里使用WordUtils表单 apachecommons-text
String name = "My Name";
String initials = WordUtils.initials(name);
System.out.println(initials); // Outputs: MN
