我有一个字符串
(之前我曾表达过这个限制条件为“不使用循环”,以防你想知道为什么每个人都试图回答而不使用循环)。
a.b.c.d
我希望以惯用方式计算“.”的出现次数,最好是一行代码解决。(之前我曾表达过这个限制条件为“不使用循环”,以防你想知道为什么每个人都试图回答而不使用循环)。
a.b.c.d
我希望以惯用方式计算“.”的出现次数,最好是一行代码解决。使用Java 8和HashMap,不需要任何库来计算所有不同字符:
private static void countChars(String string) {
HashMap<Integer, Integer> hm = new HashMap<Integer, Integer>();
string.chars().forEach(letter -> hm.put(letter, (hm.containsKey(letter) ? hm.get(letter) : 0) + 1));
hm.forEach((c, i) -> System.out.println(((char)c.intValue()) + ":" + i));
}
尝试这段代码:
package com.java.test;
import java.util.HashMap;
import java.util.Map;
public class TestCuntstring {
public static void main(String[] args) {
String name = "Bissssmmayaa";
char[] ar = new char[name.length()];
for (int i = 0; i < name.length(); i++) {
ar[i] = name.charAt(i);
}
Map<Character, String> map=new HashMap<Character, String>();
for (int i = 0; i < ar.length; i++) {
int count=0;
for (int j = 0; j < ar.length; j++) {
if(ar[i]==ar[j]){
count++;
}
}
map.put(ar[i], count+" no of times");
}
System.out.println(map);
}
}
这是最简单易懂的方法,不使用数组,只使用哈希表。它还可以计算空格、大写字母和小写字母、特殊字符等。
import java.util.HashMap;
//The code by muralidharan
public class FindChars {
public static void main(String[] args) {
findchars("rererereerererererererere");
}
public static void findchars(String s){
HashMap<Character,Integer> k=new HashMap<Character,Integer>();
for(int i=0;i<s.length();i++){
if(k.containsKey(s.charAt(i))){
Integer v =k.get(s.charAt(i));
k.put(s.charAt(i), v+1);
}else{
k.put(s.charAt(i), 1);
}
}
System.out.println(k);
}
}
输出:{r=12,e=13}
第二个输入:
findchars("The world is beautiful and $#$%%%%%%@@@@ is worst");
输出: { =7, @=4, a=2, b=1, #=1, d=2, $=2, e=2, %=6, f=1, h=1, i=3, l=2, n=1, o=2, r=2, s=3, T=1, t=2, u=2, w=2}
String s = "a.b.c.d";
int count = s.length() - deleteChars.apply( s, "." ).length(); // 3
如果您需要计算多个字符的出现次数,可以一次完成:
例如,对于b
、c
和.
:
int count = s.length() - deleteChars.apply( s, "bc." ).length(); // 5
public class Count_Characters_In_String{
public static void main(String []args){
String s = "SELENIUM";
System.out.println(s);
int counter;
String g = "";
for( int i=0; i<s.length(); i++ ) {
if(g.indexOf(s.charAt(i)) == - 1){
g=g+s.charAt(i);
}
}
System.out.println(g + " ");
for( int i=0; i<g.length(); i++ ) {
System.out.print(",");
System.out.print(s.charAt(i)+ " : ");
counter=0;
for( int j=0; j<s.length(); j++ ) {
if( g.charAt(i) == s.charAt(j) ) {
counter=counter+1;
}
}
System.out.print(counter);
}
}
}
/******************** 输出 **********************/
SELENIUM
SELNIUM
S: 1,E: 2,L: 1,E: 1,N: 1,I: 1,U: 1
public static void getCharacter(String str){
int count[]= new int[256];
for(int i=0;i<str.length(); i++){
count[str.charAt(i)]++;
}
System.out.println("The ascii values are:"+ Arrays.toString(count));
//Now display wht character is repeated how many times
for (int i = 0; i < count.length; i++) {
if (count[i] > 0)
System.out.println("Number of " + (char) i + ": " + count[i]);
}
}
}
char
是UTF-16代码单元。范围为0..Character.MAX_VALUE。如果目标是计算UTF-16代码单元的出现次数,则您的算法有效。 - Tom Blodgetpublic class OccurencesInString { public static void main(String[] args) { String str = "NARENDRA AMILINENI"; HashMap occur = new HashMap(); int count =0; String key = null; for(int i=0;i<str.length()-1;i++){ key = String.valueOf(str.charAt(i)); if(occur.containsKey(key)){ count = (Integer)occur.get(key); occur.put(key,++count); }else{ occur.put(key,1); } } System.out.println(occur); } }
我尝试使用switch语句解决您的问题,但仍需要for循环来解析字符串。如果您有任何改进代码的意见,请随时评论。
public class CharacterCount {
public static void main(String args[])
{
String message="hello how are you";
char[] array=message.toCharArray();
int a=0;
int b=0;
int c=0;
int d=0;
int e=0;
int f=0;
int g=0;
int h=0;
int i=0;
int space=0;
int j=0;
int k=0;
int l=0;
int m=0;
int n=0;
int o=0;
int p=0;
int q=0;
int r=0;
int s=0;
int t=0;
int u=0;
int v=0;
int w=0;
int x=0;
int y=0;
int z=0;
for(char element:array)
{
switch(element)
{
case 'a':
a++;
break;
case 'b':
b++;
break;
case 'c':c++;
break;
case 'd':d++;
break;
case 'e':e++;
break;
case 'f':f++;
break;
case 'g':g++;
break;
case 'h':
h++;
break;
case 'i':i++;
break;
case 'j':j++;
break;
case 'k':k++;
break;
case 'l':l++;
break;
case 'm':m++;
break;
case 'n':m++;
break;
case 'o':o++;
break;
case 'p':p++;
break;
case 'q':q++;
break;
case 'r':r++;
break;
case 's':s++;
break;
case 't':t++;
break;
case 'u':u++;
break;
case 'v':v++;
break;
case 'w':w++;
break;
case 'x':x++;
break;
case 'y':y++;
break;
case 'z':z++;
break;
case ' ':space++;
break;
default :break;
}
}
System.out.println("A "+a+" B "+ b +" C "+c+" D "+d+" E "+e+" F "+f+" G "+g+" H "+h);
System.out.println("I "+i+" J "+j+" K "+k+" L "+l+" M "+m+" N "+n+" O "+o+" P "+p);
System.out.println("Q "+q+" R "+r+" S "+s+" T "+t+" U "+u+" V "+v+" W "+w+" X "+x+" Y "+y+" Z "+z);
System.out.println("SPACE "+space);
}
}