I'm a newcomer to Java trying to submit a working project, in this instance printDuplicates. The instructions are as follows:
Write a method named printDuplicates that accepts as its parameter a Scanner for an input file containing a series of lines. Your method should examine each line looking for consecutive occurrences of the same token on the same line and print each duplicated token along how many times it appears consecutively. Non-repeated tokens are not printed. Repetition across multiple lines (such as if a line ends with a given token and the next line starts with the same token) is not considered in this problem.
For example, if the input file contains the following text:
hello how how are you you you you
I I I am Jack's Jack's smirking smirking smirking smirking smirking revenge
bow wow wow yippee yippee yo yippee yippee yay yay yay
one fish two fish red fish blue fish
It's the Muppet Show, wakka wakka wakka
Your method would produce the following output for the preceding input file:
how*2 you*4
I*3 Jack's*2 smirking*5
wow*2 yippee*2 yippee*2 yay*3
wakka*3
Your code prints only the repeated tokens; the ones that only appear once in a row are not shown. Your code should place a single space between each reported duplicate token and should respect the line breaks in the original file. This is why a blank line appears in the expected output, corresponding to the fourth line of the file that did not contain any consecutively duplicated tokens. You may assume that each line of the file contains at least 1 token of input.
Here is my code, pretty much ready for submitting.
import java.io.*;
import java.util.*;
Scanner input;
public static void printDuplicates(Scanner input) throws Exception {
String word = "";
String word2 = "";
input = new Scanner(new File("idontknowwhattodo.txt"));
while(input.hasNextLine()) {
Scanner line = new Scanner(input.nextLine());
int repeat = 1;
word = line.next();
while(line.hasNext()) {
word2 = line.next();
while(word.equals(word2)) {
repeat++;
if(line.hasNext()){
word2 = line.next();
} else {
break;
}
}
if(repeat!=1) {
System.out.print(word + "*" + repeat + " ");
}
repeat = 1;
word = word2;
}
System.out.println();
}
}
However, whenever I try to submit my project, it throws back this error:
(no output was produced!)
SecurityException on line 5:
You are not allowed to read the file /usr/share/tomcat7/temp/idontknowwhattodo.txt
java.lang.SecurityException: You are not allowed to read the file /usr/share/tomcat7/temp/idontknowwhattodo.txt
at java.io.FileInputStream.<init>(FileInputStream.java:135)
at java.io.FileReader.<init>(FileReader.java:72)
at Scanner.<init>(Scanner.java:330)
at printDuplicates (Line 5)
What does this mean? I have multiple working projects but I can't seem to submit them due to this one error. Any experts that can help me on this one? Thank you.
It looks like you are using Tomcat from your path. Tomcat requires special security permission to read or write files. This is a basic protection to prevent malicious code from accessing sensitive files on the OS. You can configure these directories or stick to reading and writing to the default ones:
https://tomcat.apache.org/tomcat-7.0-doc/security-manager-howto.html
Unable to add a comment because of reputation points so using the Answers section.
Agree with above comments, it is related to permissions.
Do an ls -ltr on /usr/share/tomcat7/temp/idontknowwhattodo.txt
Check whether the user (say myuser) with which you are running you java application has necessary permissions for /usr/share/tomcat7/temp/idontknowwhattodo.txt.
Two options below:
Give the user "myuser" the necessary permissions to the idontknowwhattodo.txt using chmod.
Or copy idontknowwhattodo.txt to a location where "myuser" has the permissions.
Problem description says that you're getting Scanner object as parameter. You don't have to recreate it, you're probably trying to submit your project to some online competition. Program on the server will load your class and call the method printDuplicates() with Scanner object as parameter, you don't have to worry about how it gets created. Just use it, and everything would be fine.
Just comment the scanner assignment line as below
String word = "";
String word2 = "";
/*input = new Scanner(new File("idontknowwhattodo.txt"));*/
while(input.hasNextLine()) {
...
As per instructions, you are already getting the Scanner object(which references the input file) as parameter to your method. So, you should not be re-initializing it.
This line should be removed:
input = new Scanner(new File("idontknowwhattodo.txt"));
Related
I have an interview task where I was given a text file with file.in format, the task said that my program should be using standard data input and output (I assume console). The input file goes something like this:
249089
439506849 989399339
773359725 989399094
33290819 989399230
771114928 989399164
823133180 989399164
615096154 989399094
340750872 989399164
41881535 989399230
637599407 989399339
510268939 989399506
46219619 989399544
221332387 989399659
236968778 989399824
902942034 989399945
936095694 989400101
**end to the line 249090**
The first number is the number of objects
The second is two numbers, but for the purpose of the task I only use the second one
For the purpose of parsing the numbers I use for loop and code below:
try (BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in)))
String line = bufferedReader.readLine();
System.out.println(line);
StringTokenizer stringTokenizer = new StringTokenizer(line, " ");//
stringTokenizer.nextToken();
int height = Integer.parseInt(stringTokenizer.nextToken());
I use IntelliJ build in console and when I paste into console i get like a couple thousands results in starting from the end, so the first number is wrong, and when i run my program i get Runtime Error:
Exception in thread "main" java.lang.NumberFormatException: For input string: "84 995058150"
at java.base/java.lang.NumberFormatException.forInputString(NumberFormatException.java:68)
at java.base/java.lang.Integer.parseInt(Integer.java:658)
at java.base/java.lang.Integer.parseInt(Integer.java:776)
at pl.artur.Main.getNumberOfBuildings(Main.java:23)
at pl.artur.Main.main(Main.java:14)
Is there a way to get around it using standard input?
This has nothing to do with where the input comes from; as the stack trace shows, the exception is thrown by the Integer.parseInt method on the string "84 995058150". This string clearly does not represent a (singular) integer. If the StringTokenizer.nextToken method returns this string, then it is StringTokenizer that's the problem. As David Conrad notes in the comments, the documentation says:
StringTokenizer is a legacy class that is retained for compatibility reasons although its use is discouraged in new code. It is recommended that anyone seeking this functionality use the split method of String or the java.util.regex package instead.
The String.split method will split line into the two parts, so you can then call Integer.parseInt on the part you want:
String line = bufferedReader.readLine();
String[] parts = line.split(" ");
int height = Integer.parseInt(parts[1]);
Ok, I resolved the issue.
The solution was to set the bigger buffer size for the console in IntelliJ settings:
I think you cannot convert or parse string including empty spaces between them to Integer.
// This string cannot be parsed to Integer directly.
// Because an empty space is included between `84` and `995058150`.
String s = "84 995058150";
If you want to parse this, you should use trim() method. example:
int intValue= Integer.parseInt(s.trim());
I hope this answer will be helpful for you.
My text file has a pattern and it's just like the following:
1;Mary Yeah;John Freeman;(12)3456-7890;iammary#gmail.com
2;Ash Wilson;One Two Three;(99)1111-2222;lorddragon#hotmail.com
3;Xin Zhao;Street Address 55;(11)0101-0202;lolyourface#gmail.com
4;My Name;My Address;My Phone;myemail#mail.com
I want to be able to type the line number, the type of data I want to replace(e-mail, phone, name), and the string I want to replace them with. The program overwrites the text.
How could I code this in Java?
The issue of how to find a given row based on the line number depends on many things, most importantly it depends on code you haven't shown us. But as for what you can do once you have found a given line, you may try the following:
String line = "2;Ash Wilson;One Two Three;(99)1111-2222;lorddragon#hotmail.com";
String[] parts = line.split(";");
parts[4] = "some.address#mail.com"; // to change the email
// now join back to a single line
line = String.join(";", Arrays.asList(parts));
Demo
First of, I am not asking for codes. I will be just asking for suggestions or ideas on how to start this project so please help me I want to learn.
INPUT TEXT FILE:
Five little monkeys jumping on the bed
One fell off and bumped his head
Mama called the doctor and the doctor said:
"No more monkeys jumping on the bed!"
OUTPUT:
Noun:
Monkeys
Doctor
(and other parts of speech)
If i remove one word from the text file it will also be gone from the Output. Is this program possible without downloading anything like the Stanford? I'm using Java. I don't know how to start it without ideas :(
Question:
What method am I going to use.
EDIT!!!!!!!!!!!
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new FileReader("C:/Users/xxxx/Desktop/lyrics.txt"));
String line = null;
while ((line = br.readLine()) != null)
{
System.out.println("Noun: ");
}
}
}
HERE NOW IT ALREADY READS MY TEXTFILE. I thought of an idea that i can just find a specific word in the text file and print it out as, "Noun: Monkeys" but without the user input. What i'm talking about is something like this one
Type word to find: ExampleWord
Output:
Sys.out.print( word + "Found!");
Can do something like this without asking for the user? It will just automatically print out every word?
I have hit a road block in a program I am writing in Java. The program basically copies folders and files from multiple locations into one folder to make backing up code from multiple locations on my computer easier. The problem I have is that I don't want to copy specific folders, in this case "workspace/.metadata". The start of the code I am having issues with is below:
public void copyFolder(File in, File out, String loc)
throws IOException{
String check = in.getName().substring(1);
System.out.println("loc:"+loc+"check: "+check);
if(loc.equals("java")){
if(check.equals("metadata")){
System.out.println("failboat");
//statusBox.append("failboat");
}
}
And this is the result I see:
loc:java
check: orkspace2
loc:java
check: metadata
loc:java
check: lock
I've had other's look at the code and they agree it should work. I've even created a replica of the code in a test file:
String test = "fmetadata";
String loc = "java";
String check = test.substring(1);
if(loc.equals("java")){
if(check.equals("metadata")){
System.out.print("failboat");
}else{
System.out.println("WTF");
System.out.print(test+ ": :"+check);
}
}
And the result?
failboat
There is a dent in my desk the size of my forehead from trying to figure this out.
If that output you posted is the actual output:
loc:java
check: orkspace2
loc:java
check: metadata
loc:java
check: lock
It does not match the code you've pasted, as you do not print a newline between the two items:
System.out.println("loc:"+loc+"check: "+check);
If this is truly what you are seeing with that code then I would say the problem is that loc has a stray newline at the end, and is actually "java\n" rather than "java" as you expect. So you should go back and examine how you generate the value you pass through loc to begin with before calling that function.
If this is the case, some suggestions for diagnostics improvements that could help you notice these kinds of issues sooner (in addition to stepping through with a debugger):
// quote your strings to spot whitespace, print length to spot unexpected
// unprintable characters.
System.out.println("loc: \""+loc+"\" "+loc.length());
System.out.println("check: \""+check+"\" "+check.length());
And:
if(loc.equals("java")){
// make sure you're getting to this point, don't assume that the first
// if condition was satisfied:
System.out.println("grumpycat"); // <----
if(check.equals("metadata")){
System.out.println("failboat");
}
}
I am working on a Java project and I am trying to get useDelimiter to remove everything except the text in between "=" and ",". For example, on the first line of the file I would like to keep "ThermostatNight".
This is what the text file looks like:
Event=ThermostatNight,time=0
Event=LightOn,time=2000
I've been able to do the exact opposite using this code:
s.useDelimiter("=(.*?),");
Is there any way I can tweak this to do the opposite?
Try this:
s.replaceAll("([a-zA-Z]*=)([a-zA-Z]*)(,.*)","$2")
This is following the pattern you show. If it changes you will have to change this regex.
See it here: http://regex101.com/r/jN8iR8
See the section Match groups, you will see that group 2 is your desired result.
The replace all method is replacing everything just for the group 2 which is what is in between = and ,
Edit
As the OP said that s is a Scanner
Scanner s = new Scanner(new File("YOURFILE"));
while (s.hasNext()) {
String text = s.next();
System.out.println( text.replaceAll("([a-zA-Z]*=)([a-zA-Z]*)(,.*)","$2") );
}
s.close();