平均字长和平均句子长度的Java代码 [英] Java Code for Average Word Length and Average Sentence Length
问题描述
好的，所以，我是一个相对较新的程序员，我在这项任务中遇到了很大的困难。该任务是创建一个2类java代码，该代码将在文件中读取，特别是一本书，并将分析它以计算平均句子长度和平均字长。正确的输出应如下所示：
Ok, so, I'm a relatively new programmer and I'm having major difficulty with this assignment. The assignment is to create a 2 class java code that will read in a file, a book specifically, and will analyze that to count average sentence length and average word length. The correct output should look something like this:
> java WordMapDriver
enter name of a file
Analyzed text: /Users/moll/CS121/AliceInWonderland.txt
words of length 1: 7.257%
words of length 2: 14.921%
words of length 3: 24.073%
words of length 4: 20.847%
words of length 5: 12.769%
words of length 6: 7.374%
words of length 7: 6.082%
words of length 8: 3.012%
words of length 9: 1.812%
words of length 10: 0.820%
words of length 11: 0.501%
words of length 12: 0.236%
words of length 13: 0.134%
words of length 14: 0.083%
words of length 15 or larger: 0.001%
average sentence length: 16.917
我一直在研究这段代码但是当我运行它时，我只是得到很多愤怒的红色错误消息。以下是一长串投诉：
I have been working on this code for a while but when I run it, I just get a lot of angry red error messages. Here is the long list of complaints:
java.lang.StringIndexOutOfBoundsException: String index out of range: 239
at java.lang.String.charAt(Unknown Source)
at WordMap.processLine(WordMap.java:26)
at Echo.readLines(Echo.java:16)
at WordMapDriver.main(WordMapDriver.java:10)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at edu.rice.cs.drjava.model.compiler.JavacCompiler.runCommand(JavacCompiler.java:272)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at edu.rice.cs.dynamicjava.symbol.JavaClass$JavaMethod.evaluate(JavaClass.java:362)
at edu.rice.cs.dynamicjava.interpreter.ExpressionEvaluator.handleMethodCall(ExpressionEvaluator.java:92)
at edu.rice.cs.dynamicjava.interpreter.ExpressionEvaluator.visit(ExpressionEvaluator.java:84)
at koala.dynamicjava.tree.StaticMethodCall.acceptVisitor(StaticMethodCall.java:121)
at edu.rice.cs.dynamicjava.interpreter.ExpressionEvaluator.value(ExpressionEvaluator.java:38)
at edu.rice.cs.dynamicjava.interpreter.ExpressionEvaluator.value(ExpressionEvaluator.java:37)
at edu.rice.cs.dynamicjava.interpreter.StatementEvaluator.visit(StatementEvaluator.java:106)
at edu.rice.cs.dynamicjava.interpreter.StatementEvaluator.visit(StatementEvaluator.java:29)
at koala.dynamicjava.tree.ExpressionStatement.acceptVisitor(ExpressionStatement.java:101)
at edu.rice.cs.dynamicjava.interpreter.StatementEvaluator.evaluateSequence(StatementEvaluator.java:66)
at edu.rice.cs.dynamicjava.interpreter.Interpreter.evaluate(Interpreter.java:77)
at edu.rice.cs.dynamicjava.interpreter.Interpreter.interpret(Interpreter.java:47)
at edu.rice.cs.drjava.model.repl.newjvm.InterpreterJVM.interpret(InterpreterJVM.java:246)
at edu.rice.cs.drjava.model.repl.newjvm.InterpreterJVM.interpret(InterpreterJVM.java:220)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.rmi.server.UnicastServerRef.dispatch(Unknown Source)
at sun.rmi.transport.Transport$1.run(Unknown Source)
at sun.rmi.transport.Transport$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Unknown Source)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(Unknown Source)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(Unknown Source)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
和这是我的代码。我非常感谢任何帮助：
And here is my code. Any help I can get is greatly appreciated:
1 import java.util.Scanner;
2 import java.io.*;
3
4 public class Echo{
5 String fileName; // external file name
6 Scanner scan; // Scanner object for reading from external file
7
8 public Echo(String f) throws IOException
9 {
10 fileName = f;
11 scan = new Scanner(new FileReader(fileName));
12}
13
14 public void readLines(){ // reads lines, hands each to processLine
15 while(scan.hasNext()){
16 processLine(scan.nextLine());
17 }
18 scan.close();
19 }
20
21 public void processLine(String line){ // does the real processing work
22 System.out.println(line);
23}
24}
___________________
1 import java.util.*;
2 import java.io.*;
3 public class WordMap extends Echo {
4 String fileName; //external text file name
5 Scanner scan; //scanner object to read external text
6 int sentencecount = 0;
7 int wordcount = 0;
8 int charcount = 0;
9 //creates an array that will be used to count average word length
10 double[] wlength = new double[15];
11 int fifteenless = 0;
12 int fifteenplus = 0;
13 public WordMap(String f) throws IOException
14 {
15 super(f);}
16
17 public void processLine(String line)
18 //creates a string array of every word
19 {String [] words = line.split("\\s+");
20 for(int a = 0; a < words.length; a++){
21 words[a] = words[a].replaceAll("[\\w]","");}
22
23 //counts words
24 wordcount = words.length;
25
26 //counts sentences by searching for sentence enders
27 for(int c = 0; c < line.length(); c++){
28 char ca = line.charAt(c);
29 if((line.charAt(ca) == '.')|| (line.charAt(ca) =='!') || (line.charAt(ca) =='?'));
30 sentencecount++ ;}
31
32 //if wordlength matches, adds one to wlength at d and to words less than 15 chars
33 for(int d = 1; d < 15; d++){
34 for(int g = 0; g < words.length; g++){
35 String temp = words[g];
36 if(d == temp.length()){
37 wlength[d]++;
38 fifteenless++;}}}}
39
40 public void calculatePercentages(){
41 {//calculate percentages with words of 15 or more characters
42 fifteenplus = wordcount - fifteenless;
43 fifteenplus = fifteenplus / wordcount;
44 fifteenplus = fifteenplus*100;}
45
46 //calculate percentages for words with 1-14 characters
47 for(int h = 1; h<15; h++){
48 wlength[h] /= wordcount;
49 wlength[h]*=100;}
50 }
51 public void reportLength(){
52 //prints out average sentence length
53 double length = wordcount / sentencecount;
54 System.out.printf("average sentence length: "+ "%5.3f",length);}
55
56 public void getWordLength(){
57 //prints out word of length percentages with a loop for 1-14 and a final one for 15+
58 for(int i = 1; i <15; i++){
59 System.out.printf("words of length " + i + ": %5.3f%%\n",wlength[i]);}
60 System.out.printf("words of 15 or more characters length: " + "%5.3f%%\n",fifteenplus);
61 }}
_______
1 import java.util.*;
2 public class WordMapDriver {
3 public static void main(String[] args) {
4 try{
5 String fileName;
6 Scanner textfile = new Scanner(System.in);
7 System.out.println("enter name of file");
8 fileName = textfile.nextLine(); //scans in file
9 WordMap k = new WordMap(fileName);//creates wordmap object
10 k.readLines(); //processes
11 k.calculatePercentages();
12 k.getWordLength(); //reports all wordlength percentages
13 k.reportLength(); //prints out average sentence length
14 }
15 catch(Exception e) //catches the ioexception
16 {e.printStackTrace();
17 }}}
*编辑：我添加了行号。此外，这可能是愚蠢的，但我不知道什么是SSCCE
** EDIT2：好的，所以我遵循了建议，现在打印出来之后是更生气的红色消息：
* I added line numbers. Also, this may be dumb, but I don't know what SSCCE ** Ok, so I followed advice and now it prints this followed by more angry red messages:
words of length 1: 50620.000%
words of length 2: 15690.000%
words of length 3: 2020.000%
words of length 4: 300.000%
words of length 5: 620.000%
words of length 6: 70.000%
words of length 7: 20.000%
words of length 8: 10.000%
words of length 9: 0.000%
words of length 10: 10.000%
words of length 11: 10.000%
words of length 12: 10.000%
words of length 13: 10.000%
words of length 14: 0.000%
words of 15 or more characters length: java.util.IllegalFormatConversionException: f != java.lang.Integer
推荐答案
看看这一部分：
for(int c = 0; c < line.length(); c++){
char ca = line.charAt(c);
if((line.charAt(ca) == '.')|| (line.charAt(ca) =='!') || (line.charAt(ca) =='?'));
sentencecount++ ;}
这里有两个问题：
-
变量ca是索引c处的字符。但是你将ca传递给line.charAt ... Java正在帮助将char转换为int，并尝试返回该索引处的字符。这不是你想要的，这就是你得到StringIndexOutOfBoundsException的原因。
The variable "ca" is the character at index c. But you're passing "ca" to line.charAt... Java is "helpfully" converting the char to an int, and trying to return the character at that index. That's not what you want, and it's why you're getting the StringIndexOutOfBoundsException.
你可能只想在表达式为真时增加sentenceCount，对吗？这不是代码所说的。这个if语句没有正文（因为与if语句在同一行上的分号）。一个好的做法，特别是初学者，是总是使用花括号来封闭if块的主体，即使它们只是一行。
You probably want to increment sentenceCount only if the expression is true, right? That's not what the code says. This "if" statement has no body (because of the semicolon on the same line as the "if" statement). A good practice, especially for beginners, is to always use curly braces to enclose the body of if blocks, even if they are only one line.
至于IllegalFormatConversionException，它告诉你％5.3f不是整数的有效转换模式（ f用于浮动和双打）。 fifteenplus被声明为int;是正确的类型？如果是这样，您可以像这样打印：
As for the IllegalFormatConversionException, it's telling you that %5.3f is not a valid conversion pattern for an integer ("f" is for floats and doubles). fifteenplus is declared as an int; is that the correct type? If so, you can just print it like this:
System.out.println("words of 15 or more characters length: " + fifteenplus);
如果你的意思是像所有其他行一样的百分比，那么你应该声明它为一个浮点数或双倍（通常你应该更喜欢双浮点数，因为双打提供更多的精度，性能差异通常是微不足道的。）
If you mean for it to be a percentage like all the other lines, then you should declare it as a float or double (generally you should prefer doubles over floats because doubles offer more precision and the performance difference is usually insignificant).
最后一点：不是很奇怪所有百分比都以.000％结尾？在Java中，将int除以int总是会给出一个int。如果你想要一个浮点结果，你必须将其中一个参数转换为float或double，如下所示：
One final point: Isn't it strange that all of your percentages end in .000%? In Java, dividing an int by an int always gives you an int. If you want a floating point result, you must cast one of the arguments to a float or double, like this:
int a = 1;
int b = 2;
double result = (double) a / b;
尝试使用和不使用强制转换加倍看看差异。
Try that with and without the cast to double to see the difference.
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