I know how to save data pretty easily with the printWriter to a txt file etc.
I have a mineSweeper game that saves the name, boardsize, time taken for completion and how many mines were used; the file looks like this:
name
10x10
00:00:01
20
gap
repeat
but trying to get this to be sorted is going to be a very difficult ordeal as none of this data when saved in a file is technically "related.
Are there any ways of saving this data so they are some what related.
I was thinking of saving it in one big long string with break character at the end and between such as
name + "!!" + boardSize + "!!" + time + "!!" + mines + "!?" < as the end break
any help would be great, thanks.
You can save the data as xml:
<root>
<name>...</name>
<boardsize>...</boardsize>
.
.
.
</root>
This way you will be maintain relationship with your data when extracting it back from file
The easiest way to do this would probably be sqlLite, it's portable and fairly straight forward to use, Tutorial point have a pretty good example of how to set it up and use it - http://www.tutorialspoint.com/sqlite/sqlite_java.htm
Might also be worth looking into joins if you want to store related data in seperare tables - http://www.tutorialspoint.com/sqlite/sqlite_using_joins.htm
Keep it simple, create a model of a game session
define a class of that a serialize it to lets say json
{name:xoce, size:10x10, time:00:00:01, mines:20}
when this step is ready, append every game result to a Txtfile and if you want to sort, then read the file, deserialize it to a json list and sort the list with the anonymous Comparator so you can play with your best sort criteria
How about creating a Game class which will contain all the necessary attributes - name, boardSize, ... - and will implement Serializable and Comparable<T> so you can sort it in an array later.
Then you can simply save it to a file using ObjectOutputStream.
List<Game> gamesList = ...; // I suppose you have a list of games you want to store
ObjectOutputStream oos = new ObjectOutputStream(...);
oos.writeObject(gamesList);
...
Try as I might, I cannot figure out how to solve this program. I apologize for its cheesiness, I'm a student learning java and was given this as a practice.
Lixnor is a mutant space trader in the Andromeda IV galaxy. He is low on
supplies and funds and has trouble paying for the fuel that his ship
requires. Every SGW (Standard Galactic Week) his partner, Ronxil gives him
the coordinates for 2 valuable lost crates floating in space. The
coordinates are sent in a file named "Coordinates.txt". The files always
have 3 lines, each line containing a coordinate in the format (x,y,z) where
x,y,z are integers. Due to Lixnor's lack of funds, he must first calculate
whether it would be worth it for him to go pick them up. The first
coordinates given are Lixnor's current coordinates, and the next two are the
coordinates of the two crates. Lixnor must pick them up, then return to his
original location. Write a program for Lixnor that calculates the distance
he must travel in order to pick up the crates and return to his original
position.
(24,-34,46)
(1,2,3)
(123,-1,0)
Specifically, I'm having trouble getting Java to read the file. Any help would be fantastic!
Reading a file is simple
Get the file instance using File file = new File(String fileAddress);
Now use Scanner scanner = new Scanner(file); to read the file.
Proceed and show us the work for further help.
I agree with #ImGeorge that before doing this work get some basic knowledge about File Reader.
At SO we cannot help without code.
Look into the javadoc of Files.readAllLines.
Path path = Paths.get(".... .txt");
List<String> lines = Files.readAllLines(path); // Using UTF-8
This is one of the possibilities. The processing is up to you.
I'm pretty much a complete newbie to java and programming in general. I was wondering if anyone could help me out.
So I have a .csv that I am reading and storing data from (i think in the form of an array?) by using the following. This works fine and is grabbing all the data from the csv.
fo=new File()
fo.open(filename)
contents = fo.read()
fo.close
The data that I am grabbing from the .csv is in the form of well positions on a plate e.g. A1, B1, C1, D1 etc. Now is there a way that I can make each of the letters worth a particular value?
For example, A=1, B=2 C=3 etc, and then make this new value multiply by the second number e.g. A1 would become 1*1 = 2 and A2 would become 1*2 = 2 and B2 would become 2*2 = 4.
Any help would be greatly appreciated.
Usually the way that files are read follow this structure:
Open File using Reader. (using Scanner, FileReader, etc)
Read data. (Scanner.nextLine() for example)
Close File Reader. (close)
In your case, one possible approach is to read the data and then if you want an array of values, simply use String.split() method, passing the "," as a delimiter because it is comma separated file. Once you have an array, you make w/e changes you want. In your case, you want to iterate over that array and perform transformations.
However, I would also like to clarify something, because it is kind of implied by your question, that updating the array after you read will not update the file. Just wanted to make that clear to avoid confusion.
Okay so i am working on a game based on a Trading card game in java. I Scraped all of the game peices' "information" into a csv file where each row is a game peice and each column is a type of attribute for that peice. I have spent hours upon hours writing code with Buffered reader and etc. trying to extract the information from my csv file into a 2d Array but to no avail. My csv file is linked Here: http://dl.dropbox.com/u/3625527/MonstersFinal.csv I have one year of computer science under my belt but I still cannot figure out how to do this.
So my main question is how do i place this into a 2D array that way i can keep the rows and columns?
Well, as mentioned before, some of your strings contain commas, so initially you're starting from a bad place, but I do have a solution and it's this:
--------- If possible, rescrape the site, but perform a simple encoding operation when you do. You'll want to do something like what you'll notice tends to be done in autogenerated XML files which contain HTML; reserve a 'control character' (a printable character works best, here, for reasons of debugging and... well... sanity) that, once encoded, is never meant to be read directly as an instance of itself. Ampersand is what I like to use because it's uncommon enough but still printable, but really what character you want to use is up to you. What I would do is write the program so that, at every instance of ",", that comma would be replaced by "&c" before being written to the CSV, and at every instance of an actual ampersand on the site, that "&" would be replaced by "&a". That way, you would never have the issue of accidentally separating a single value into two in the CSV, and you could simply decode each value after you've separated them by the method I'm about to outline in...
-------- Assuming you know how many columns will be in each row, you can use the StringTokenizer class (look it up- it's awesome and built into Java. A good place to look for information is, as always, the Java Tutorials) to automatically give you the values you need in the form of an array.
It works by your passing in a string and a delimiter (in this case, the delimiter would be ','), and it spitting out all the substrings which were separated by those commas. If you know how many pieces there are in total from the get-go, you can instantiate a 2D array at the beginning and just plug in each row the StringTokenizer gives them to you. If you don't, it's still okay, because you can use an ArrayList. An ArrayList is nice because it's a higher-level abstraction of an array that automatically asks for more memory such that you can continue adding to it and know that retrieval time will always be constant. However, if you plan on dynamically adding pieces, and doing that more often than retrieving them, you might want to use a LinkedList instead, because it has a linear retrieval time, but a much better relation than an ArrayList for add-remove time. Or, if you're awesome, you could use a SkipList instead. I don't know if they're implemented by default in Java, but they're awesome. Fair warning, though; the cost of speed on retrieval, removal, and placement comes with increased overhead in terms of memory. Skip lists maintain a lot of pointers.
If you know there should be the same number of values in each row, and you want them to be positionally organized, but for whatever reason your scraper doesn't handle the lack of a value for a row, and just doesn't put that value, you've some bad news... it would be easier to rewrite the part of the scraper code that deals with the lack of values than it would be to write a method that interprets varying length arrays and instantiates a Piece object for each array. My suggestion for this would again be to use the control character and fill empty columns with &n (for 'null') to be interpreted later, but then specifics are of course what will individuate your code and coding style so it's not for me to say.
edit: I think the main thing you should focus on is learning the different standard library datatypes available in Java, and maybe learn to implement some of them yourself for practice. I remember implementing a binary search tree- not an AVL tree, but alright. It's fun enough, good coding practice, and, more importantly, necessary if you want to be able to do things quickly and efficiently. I don't know exactly how Java implements arrays, because the definition is "a contiguous section of memory", yet you can allocate memory for them in Java at runtime using variables... but regardless of the specific Java implementation, arrays often aren't the best solution. Also, knowing regular expressions makes everything much easier. For practice, I'd recommend working them into your Java programs, or, if you don't want to have to compile and jar things every time, your bash scripts (if your using *nix) and/or batch scripts (if you're using Windows).
I think the way you've scraped the data makes this problem more difficult than it needs to be. Your scrape seems inconsistent and difficult to work with given that most values are surrounded by quotes inconsistently, some data already has commas in it, and not each card is on its own line.
Try re-scraping the data in a much more consistent format, such as:
R1C1|R1C2|R1C3|R1C4|R1C5|R1C6|R1C7|R1C8
R2C1|R2C2|R2C3|R2C4|R2C5|R2C6|R2C7|R3C8
R3C1|R3C2|R3C3|R3C4|R3C5|R3C6|R3C7|R3C8
R4C1|R4C2|R4C3|R4C4|R4C5|R4C6|R4C7|R4C8
A/D Changer|DREV-EN005|Effect Monster|Light|Warrior|100|100|You can remove from play this card in your Graveyard to select 1 monster on the field. Change its battle position.
Where each line is definitely its own card (As opposed to the example CSV you posted with new lines in odd places) and the delimiter is never used in a data field as something other than a delimiter.
Once you've gotten the input into a consistently readable state, it becomes very simple to parse through it:
BufferedReader br = new BufferedReader(new FileReader(new File("MonstersFinal.csv")));
String line = "";
ArrayList<String[]> cardList = new ArrayList<String[]>(); // Use an arraylist because we might not know how many cards we need to parse.
while((line = br.readLine()) != null) { // Read a single line from the file until there are no more lines to read
StringTokenizer st = new StringTokenizer(line, "|"); // "|" is the delimiter of our input file.
String[] card = new String[8]; // Each card has 8 fields, so we need room for the 8 tokens.
for(int i = 0; i < 8; i++) { // For each token in the line that we've read:
String value = st.nextToken(); // Read the token
card[i] = value; // Place the token into the ith "column"
}
cardList.add(card); // Add the card's info to the list of cards.
}
for(int i = 0; i < cardList.size(); i++) {
for(int x = 0; x < cardList.get(i).length; x++) {
System.out.printf("card[%d][%d]: ", i, x);
System.out.println(cardList.get(i)[x]);
}
}
Which would produce the following output for my given example input:
card[0][0]: R1C1
card[0][1]: R1C2
card[0][2]: R1C3
card[0][3]: R1C4
card[0][4]: R1C5
card[0][5]: R1C6
card[0][6]: R1C7
card[0][7]: R1C8
card[1][0]: R2C1
card[1][1]: R2C2
card[1][2]: R2C3
card[1][3]: R2C4
card[1][4]: R2C5
card[1][5]: R2C6
card[1][6]: R2C7
card[1][7]: R3C8
card[2][0]: R3C1
card[2][1]: R3C2
card[2][2]: R3C3
card[2][3]: R3C4
card[2][4]: R3C5
card[2][5]: R3C6
card[2][6]: R3C7
card[2][7]: R4C8
card[3][0]: R4C1
card[3][1]: R4C2
card[3][2]: R4C3
card[3][3]: R4C4
card[3][4]: R4C5
card[3][5]: R4C6
card[3][6]: R4C7
card[3][7]: R4C8
card[4][0]: A/D Changer
card[4][1]: DREV-EN005
card[4][2]: Effect Monster
card[4][3]: Light
card[4][4]: Warrior
card[4][5]: 100
card[4][6]: 100
card[4][7]: You can remove from play this card in your Graveyard to select 1 monster on the field. Change its battle position.
I hope re-scraping the information is an option here and I hope I haven't misunderstood anything; Good luck!
On a final note, don't forget to take advantage of OOP once you've gotten things worked out. a Card class could make working with the data even simpler.
I'm working on a similar problem for use in machine learning, so let me share what I've been able to do on the topic.
1) If you know before you start parsing the row - whether it's hard-coded into your program or whether you've got some header in your file that gives you this information (highly recommended) - how many attributes per row there will be, you can reasonably split it by comma, for example the first attribute will be RowString.substring(0, RowString.indexOf(',')), the second attribute will be the substring from the first comma to the next comma (writing a function to find the nth instance of a comma, or simply chopping off bits of the string as you go through it, should be fairly trivial), and the last attribute will be RowString.substring(RowString.lastIndexOf(','), RowString.length()). The String class's methods are your friends here.
2) If you are having trouble distinguishing between commas which are meant to separate values, and commas which are part of a string-formatted attribute, then (if the file is small enough to reformat by hand) do what Java does - represent characters with special meaning that are inside of strings with '\,' rather than just ','. That way you can search for the index of ',' and not '\,' so that you will have some way of distinguishing your characters.
3) As an alternative to 2), CSVs (in my opinion) aren't great for strings, which often include commas. There is no real common format to CSVs, so why not make them colon-separated-values, or dash-separated-values, or even triple-ampersand-separated-values? The point of separating values with commas is to make it easy to tell them apart, and if commas don't do the job there's no reason to keep them. Again, this applies only if your file is small enough to edit by hand.
4) Looking at your file for more than just the format, it becomes apparent that you can't do it by hand. Additionally, it would appear that some strings are surrounded by triple double quotes ("""string""") and some are surrounded by single double quotes ("string"). If I had to guess, I would say that anything included in a quotes is a single attribute - there are, for example, no pairs of quotes that start in one attribute and end in another. So I would say that you could:
Make a class with a method to break a string into each comma-separated fields.
Write that method such that it ignores commas preceded by an odd number of double quotes (this way, if the quote-pair hasn't been closed, it knows that it's inside a string and that the comma is not a value separator). This strategy, however, fails if the creator of your file did something like enclose some strings in double double quotes (""string""), so you may need a more comprehensive approach.
I am new to this place and in need of serious help. After spending 6 hours trying to figure out this, I am going insane and need help. Here is the question i am assigned.
Create the StandardDeviation project. Write a java program that reads a set of double data values. When all the values have been read, print out the count of the values, the average and the standard deviation.
I cannot find any commands that allow for a group of entered numbers at once and be read by JAVA. Could someone please help me get started or point to somewhere where i can find relative problems or examples. Thank you very much. All i know is that it supposed to start with
while (in.hasNextDouble())
I'm assuming this is homework.
You're going to want to look at java.util.Scanner, it will let you do while( Scanner.hasNextDouble() ) which you can then sum. You're also going to want to keep track of all the numbers so you should take a look at java.util.ArrayList.
Note: to use ArrayList properly you'll have to use the Double class, which can be treated almost exactly like a double primitive, or you can use arrays instead of ArrayList.
Take a look at the Scanner class. It can read input data and you can repeatedly call hasNextDouble and nextDouble on it to pull out the data.
From javaman (http://www.daniweb.com/members/javaman2/471995) I find a solution. It looks like the Scanner class provides capabilities in this area also.