如何计算java字符串中的空格？
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how to count the spaces in a java string?
提问by kamweshi
I need to count the number of spaces in my string but my code gives me a wrong number when i run it, what is wrong?
我需要计算字符串中的空格数，但是我的代码在运行时给出了错误的数字，有什么问题？
int count=0;
String arr[]=s.split("\t");
OOPHelper.println("Number of spaces are: "+arr.length);
count++;
回答by nikhil500
Your code will count the number of tabs and not the number of spaces. Also, the number of tabs will be one less than arr.length.
您的代码将计算制表符的数量而不是空格的数量。此外，选项卡的数量将比 少 1 arr.length。
回答by Kurt Kaylor
The code you provided would print the number of tabs, not the number of spaces. The below function should count the number of whitespace characters in a given string.
您提供的代码将打印制表符的数量，而不是空格的数量。下面的函数应该计算给定字符串中的空白字符数。
int countSpaces(String string) {
int spaces = 0;
for(int i = 0; i < string.length(); i++) {
spaces += (Character.isWhitespace(string.charAt(i))) ? 1 : 0;
}
return spaces;
}
回答by chooban
\twill match tabs, rather than spaces and should also be referred to with a double slash: \\t. You could call s.split( " " )but that wouldn't count consecutive spaces. By that I mean...
\t将匹配制表符，而不是空格，也应该用双斜线表示：\\t。你可以打电话，s.split( " " )但这不会计算连续的空格。我的意思是...
String bar = " ba jfjf jjj j ";
String[] split = bar.split( " " );
System.out.println( split.length ); // Returns 5
So, despite the fact there are seven space characters, there are only five blocks of space. It depends which you're trying to count, I guess.
因此，尽管有七个空格字符，但只有五个空格。我猜这取决于你要数哪个。
Commons Langis your friend for this one.
Commons Lang是你的朋友。
int count = StringUtils.countMatches( inputString, " " );
回答by AlexR
s.length() - s.replaceAll(" ", "").length()returns you number of spaces.
s.length() - s.replaceAll(" ", "").length()返回您的空格数。
There are more ways. For example"
还有更多的方法。例如”
int spaceCount = 0;
for (char c : str.toCharArray()) {
if (c == ' ') {
spaceCount++;
}
}
etc., etc.
等等等等。
In your case you tried to split string using \t- TAB. You will get right result if you use " "instead. Using \smay be confusing since it matches all whitepsaces- regular spaces and TABs.
在您的情况下，您尝试使用\t- TAB拆分字符串。如果您" "改为使用，您将获得正确的结果。使用\s可能会令人困惑，因为它匹配所有空白- 常规空格和制表符。
回答by Bohemian
Here's a different way of looking at it, and it's a simple one-liner:
这是一种不同的看待它的方式，它是一个简单的单行：
int spaces = s.replaceAll("[^ ]", "").length();
This works by effectively removing all non-spaces then taking the length of what's left (the spaces).
这通过有效地删除所有非空格然后取剩下的长度（空格）来工作。
You might want to add a null check:
您可能想要添加一个空检查：
int spaces = s == null ? 0 : s.replaceAll("[^ ]", "").length();
Java 8 update
Java 8 更新
You can use a stream too:
您也可以使用流：
int spaces = s.chars().filter(c -> c == (int)' ').count();
回答by Peter Lawrey
Another way using regular expressions
使用正则表达式的另一种方式
int length = text.replaceAll("[^ ]", "").length();
回答by Adam
A solution using java.util.regex.Pattern / java.util.regex.Matcher
使用 java.util.regex.Pattern / java.util.regex.Matcher 的解决方案
String test = "foo bar baz ";
Pattern pattern = Pattern.compile(" ");
Matcher matcher = pattern.matcher(test);
int count = 0;
while (matcher.find()) {
count++;
}
System.out.println(count);
回答by Konstantin Pribluda
Fastest way to do this would be:
最快的方法是：
int count = 0;
for(int i = 0; i < str.length(); i++) {
if(Character.isWhitespace(str.charAt(i))) count++;
}
This would catch all characters that are considered whitespace.
这将捕获所有被视为空白的字符。
Regex solutions require compiling regex and excecuting it - with a lot of overhead. Getting character array requires allocation. Iterating over byte array would be faster, but only if you are sure that your characters are ASCII.
正则表达式解决方案需要编译正则表达式并执行它 - 有很多开销。获取字符数组需要分配。迭代字节数组会更快，但前提是您确定您的字符是 ASCII。
回答by S N Prasad Rao
please check the following code, it can help
请检查以下代码，它可以帮助
public class CountSpace {
public static void main(String[] args) {
String word = "S N PRASAD RAO";
String data[];int k=0;
data=word.split("");
for(int i=0;i<data.length;i++){
if(data[i].equals(" ")){
k++;
}
}
System.out.println(k);
}
}
回答by James Drinkard
I just had to do something similar to this and this is what I used:
我只需要做类似的事情，这就是我使用的：
String string = stringValue;
String[] stringArray = string.split("\s+");
int length = stringArray.length;
System.out.println("The number of parts is: " + length);
