java 如何计算java中字符串中字符的出现次数
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How to count occurrences of a character in a String in java
提问by FabianG
Can someone tell me, how can I do an if-clause, that say me how often I used the decimal seperator in this String.
有人能告诉我，我怎么能做一个 if 子句，说我在这个字符串中使用十进制分隔符的频率。
i.e.: 1234,56,789
即：1234,56,789
回答by Jim
String number = "1234,56,789";
int commaCount = number.replaceAll("[^,]*", "").length();
回答by óscar López
Simple enough:
足够简单：
String number = "1234,56,789";
int count = 0;
for (int i = 0; i < number.length(); i++)
if (number.charAt(i) == ',')
count++;
// count holds the number of ',' found
回答by óscar López
I think the simpliest way is to exucute a String.split(",")and count the size of array.
我认为最简单的方法是执行 aString.split(",")并计算数组的大小。
So the instruction willl look like this :
所以指令看起来像这样：
String s = "1234,56,789";
int numberofComma = s.split(",").length;
Regards, éric
问候，埃里克
回答by Guillaume USE
If you can use an non-if-clause, you can do :
如果您可以使用非 if 子句，则可以执行以下操作：
int count = number.split(",").length
回答by pushp priyadarshi
public class OccurenceOfChar {
public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter any word");
String s=br.readLine();
char ch[]=s.toCharArray();
Map map=new HashMap();
for(int i=0;i<ch.length;i++)
{
int count=0;
for(int j=0;j<ch.length;j++)
{
if(ch[i]==ch[j])
count++;
}
map.put(ch[i], count);
}
Iterator it=map.entrySet().iterator();
while(it.hasNext())
{
Map.Entry pairs=(Map.Entry)it.next();
System.out.println("count of "+pairs.getKey() + " = " + pairs.getValue());
}
}
}
回答by Chandra Sekhar
You don't need any if-clause, just use
您不需要任何 if 子句，只需使用
String s = "1234,56,78";
System.out.println(s.split(",").length);
