[英](Java) Counting letters in a sentence?
以下是我的代碼:
char[] array = new char[26] ;
int index = 0 ;
int letter = 0 ;
int countA = 0 ;
String sentence = "Once upon a time..." ;
if(sentence.contains("."))
{
String sentenceNoSpace = sentence.replace(" ", "").toLowerCase() ;
String sentenceFinal = sentenceNoSpace.substring(0, sentenceNoSpace.indexOf(".")) ;
char[] count = new char[sentenceFinal.length()] ;
for (char c = 'a'; c <= 'z'; c++)
{
array[index++] = c ;
for(int i = 0; i < sentenceFinal.length(); i++)
{
if(sentenceFinal.charAt(i) == c)
count[letter++] = c ;
//if(sentenceFinal.charAt(i) == 'a')
//countA++ ;
}
}
String result = new String(count) ; // Convert to a string.
System.out.println("\n" + result) ;
System.out.println("\nTotal number of letters is " + result.length()) ;
System.out.println(countA) ;
}
else
{
System.out.println("You forgot a period. Try again.") ;
}
我無法計算給定句子中有多少個a,b,c等。 我有一種方法可以做到,這就是這一部分
//if(sentenceFinal.charAt(i) == 'a')
//countA++ ;
我可以一直創建到z 有沒有更有效的方法?
注意:請勿使用Hashmap或任何其他高級技術。
無需消除空間。 這只是您正在做的其他工作。
int countOfLetters = 0 ;
String sentence = "Once upon a time..." ;
sentence = sentence.toLowerCase();
int[] countOfAlphabets = new int[26];
for (int i = 0; i < sentence.length(); i++) {
if (sentence.charAt(i) >= 'a' && sentence.charAt(i) <= 'z') {
countOfAlphabets[sentence.charAt(i) - 97]++;
countOfLetters++;
}
}
因此, countOfLetters
將為您提供字母的總數。 例如,如果您要進行個體計數,則您想計數'c' ,
您可以通過訪問countOfAlphabets
數組(例如countOfAlphabets['c' - 97]
(97是'a'的ASCII值))來獲取它
使用int
數組letterCounts
將存儲每個字母的計數。 假設字母的大小寫可以忽略,則letterCounts
數組的長度為26。
遍歷字符串的字符並更新數組中的相應整數。 使用其ASCII值查找相應的索引,如下所示。
letterCounts[c - 97]++
ASCII值“ a”為97,其計數需要存儲在索引0中。
這樣,從字符的ASCII值中減去97將得到該字符的相應索引。
注意:這是假設您要存儲小寫字母的計數。
不用地圖就可以了,但這會計算字符串中的所有字符。
您可能需要修改以排除空格等內容。
public class Main {
public static void main(String[] args) {
String sentence = "Once upon a time...";
// Create an array of size 256 ASCII_SIZE
int count[] = new int[256];
int length = sentence.length();
// Initialize count array index
for (int i = 0; i < length; i++)
count[sentence.charAt(i)]++;
// Create an array of given String size
char chars[] = new char[sentence.length()];
for (int i = 0; i < length; i++) {
chars[i] = sentence.charAt(i);
int find = 0;
for (int j = 0; j <= i; j++) {
// If any matches found
if (sentence.charAt(i) == chars[j])
find++;
}
if (find == 1) {
System.out.println("Occurrence of " + sentence.charAt(i) + " is:" + count[sentence.charAt(i)]);
}
}
}
}
哪個輸出:
Occurrence of O is:1
Occurrence of n is:2
Occurrence of c is:1
Occurrence of e is:2
Occurrence of is:3
Occurrence of u is:1
Occurrence of p is:1
Occurrence of o is:1
Occurrence of a is:1
Occurrence of t is:1
Occurrence of i is:1
Occurrence of m is:1
Occurrence of . is:3
檢查下面的代碼您可以具有26個長度的數組,索引將根據字母的存在而增加。
public void getResult(){
int [] charCount = new int [26];
int countA = 0 ;
String sentence = "Once upon a time..." ;
if(sentence.contains("."))
{
String sentenceNoSpace = sentence.replace(" ", "").toLowerCase() ;
String sentenceFinal = sentenceNoSpace.substring(0, sentenceNoSpace.indexOf(".")) ;
char[] sentenceCharArray = sentenceFinal.toCharArray();
//char a = 97;
for (int i = 0; i <sentenceCharArray.length ; i++) {
int index = sentenceCharArray[i] - 97 ;
if(index >= 0 && index <= 26) {
charCount[index] += 1;
}
}
System.out.print("Result : ");
for (int i = 0; i < charCount.length ; i++) {
System.out.print(charCount [i]+" , ");
}
System.out.println("\nTotal number of letters is " + sentenceCharArray.length) ;
}
else
{
System.out.println("You forgot a period. Try again.") ;
}
}
由於美國字母表中有26個字母,因此您可以使用大小為26的int[]
int[] letterCount = new int[26];
保留每個字母的計數,其中索引0代表'a',1代表'b',依此類推...
當您遍歷句子時,請檢查您所使用的字符是否為字母Character.isLetter()
,然后遞增表示字母的數組中的元素。
letterCount[letter - 'a']++;
我們從字母中減去“ a”來給我們正確的索引。
package stackoverflow;
public class Question {
public static void main(String[] args) {
String sentence = "The quick brown fox jumps over the lazy dog.";
int[] letterCount = new int[26];
if (sentence.contains(".")) {
// toLowerCase() the sentence since we count upper and lowercase as the same
for (char letter : sentence.toLowerCase().toCharArray()) {
if (Character.isLetter(letter)) {
letterCount[letter - 'a']++;
}
}
// Display the count of each letter that was found
int sumOfLetters = 0;
for (int i = 0; i < letterCount.length; i++) {
int count = letterCount[i];
if (count > 0) {
System.out.println((char)(i + 'a') + " occurs " + count + " times");
sumOfLetters += count;
}
}
System.out.println("Total number of letters is " + sumOfLetters);
} else {
System.out.println("You forgot a period. Try again.");
}
}
}
a occurs 1 times
b occurs 1 times
c occurs 1 times
d occurs 1 times
e occurs 3 times
f occurs 1 times
g occurs 1 times
h occurs 2 times
i occurs 1 times
j occurs 1 times
k occurs 1 times
l occurs 1 times
m occurs 1 times
n occurs 1 times
o occurs 4 times
p occurs 1 times
q occurs 1 times
r occurs 2 times
s occurs 1 times
t occurs 2 times
u occurs 2 times
v occurs 1 times
w occurs 1 times
x occurs 1 times
y occurs 1 times
z occurs 1 times
Total number of letters is 35
使用Java 8和使用String
的chars()
有什么問題? 有了它,您可以用更少的代碼完成相同的事情。 對於字母總數,我們只使用String.replaceAll()
並使用[^A-Za-z]
模式從String
刪除所有非字母,然后使用結果的length()
。
package stackoverflow;
import java.util.function.Function;
import java.util.stream.Collectors;
public class Question {
public static void main(String[] args) {
String sentence = "The quick brown fox jumps over the lazy dog.";
System.out.println(sentence.toLowerCase().chars()
// Change the IntStream to a stream of Characters
.mapToObj(c -> (char)c)
// Filter out non lower case letters
.filter(c -> 'a' <= c && c <= 'z')
// Collect up the letters and count them
.collect(Collectors.groupingBy(Function.identity(), Collectors.counting())));
System.out.println("Total letter count is " + sentence.replaceAll("[^A-Za-z]", "").length());
}
}
{a=1, b=1, c=1, d=1, e=3, f=1, g=1, h=2, i=1, j=1, k=1, l=1, m=1, n=1, o=4, p=1, q=1, r=2, s=1, t=2, u=2, v=1, w=1, x=1, y=1, z=1}
Total letter count is 35
如果Regex
不會被視為高科技If,則可以使用Regex解決。
想法很簡單: 刪除所有字母,然后從原始字符串長度中減去輸出以得到計數器
String sentence = "Once upon a time...";
String noLetterString = sentence.replaceAll("[a-zA-Z]", "");
int counterLetter = sentence.length() - noLetterString.length();
System.out.println("counter:" + counterLetter);
通過老派編程🙂這里的想法是相反的,僅添加字母
String sentence = "Once upon a time...";
String lowerCase = sentence.toLowerCase(); // to avoid comparison to UpperCase letters
StringBuilder counterStr = new StringBuilder();
for (char l : lowerCase.toCharArray()) {
if (l >= 'a' && l <= 'z') {
counterStr.append(l);
}
}
System.out.println("counterStr:" + counterStr);
System.out.println("counter:" + counterStr.length());
這是更新代碼:
int[] array = new int[26] ;
String sentence = "Once upon a time..." ;
if(sentence.contains("."))
{
String sentenceNoSpace = sentence.replace(" ", "").toLowerCase() ;
String sentenceFinal = sentenceNoSpace.substring(0, sentenceNoSpace.indexOf(".")) ;
for (char c : sentenceFinal.toCharArray())
{
System.out.println(c+" "+(c-97));
array[c-97] += 1;
}
// System.out.println("\n" + Arrays.toString(array)) ;
for(int i=0; i< array.length;i++) {
if(array[i] != 0) {
char c = (char)(i+97);
System.out.println(c+" occured "+ array[i]+" times");
}
}
}
else
{
System.out.println("You forgot a period. Try again.") ;
}
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