I want to get a string[] assigned with a StreamReader. Like:
try{
StreamReader sr = new StreamReader("a.txt");
do{
str[i] = sr.ReadLine();
i++;
}while(i < 78);
}
catch (Exception ex){
MessageBox.Show(ex.ToString());
}
I can do it but can't use the string[]. I want to do this:
MessageBox.Show(str[4]);
If you need further information feel free to ask, I will update.
thanks in advance...
If you really want a string array, I would approach this slightly differently. Assuming you have no idea how many lines are going to be in your file (I'm ignoring your hard-coded value of 78 lines), you can't create a string[] of the correct size up front.
Instead, you could start with a collection of strings:
var list = new List<string>();
Change your loop to:
using (var sr = new StreamReader("a.txt"))
{
string line;
while ((line = sr.ReadLine()) != null)
{
list.Add(line);
}
}
And then ask for a string array from your list:
string[] result = list.ToArray();
Update
Inspired by Cuong's answer, you can definitely shorten this up. I had forgotten about this gem on the File class:
string[] result = File.ReadAllLines("a.txt");
What File.ReadAllLines does under the hood is actually identical to the code I provided above, except Microsoft uses an ArrayList instead of a List<string>, and at the end they return a string[] array via return (string[]) list.ToArray(typeof(string));.
Related
I'm writing a C# program using XML and Linq that reads in data from tables stored in a word document and inserts it into an excel spreadsheet. The code I have so far does this, however it does not preserve any new lines (in the word doc the "new line" is done by pressing the enter key). Using the debugger, I can see that the new lines aren't even being read in. For example, if the text I want to copy is:
Something like this
And another line
And maybe even a third line
It gets read in as:
Something like thisAnd another lineAnd maybe even a third line
I can't separate the lines by a character as the words could be anything. This is what I have so far:
internal override Dictionary<string, string> GetContent()
{
Dictionary<string, string> contents = new Dictionary<string, string>();
using (WordprocessingDocument doc = WordprocessingDocument.Open(MainForm.WordFileDialog.FileName, false))
{
List<Table> tables = doc.MainDocumentPart.Document.Descendants<Table>().ToList();
foreach (Table table in tables)
{
TableRow headerRow = table.Elements<TableRow>().ElementAt(0);
TableCell tableSectionTitle;
try
{
tableSectionTitle = headerRow.Elements<TableCell>().ElementAt(0);
}
catch (ArgumentOutOfRangeException)
{
continue;
}
List<TableRow> rows = table.Descendants<TableRow>().ToList();
foreach (TableRow row in rows)
{
TableCell headerCell = row.Elements<TableCell>().ElementAt(0);
if (headerCell.InnerText.ToLower().Contains("first item"))
{
contents.Add("first item", row.Elements<TableCell>().ElementAt(1).InnerText);
}
else if (headerCell.InnerText.ToLower().Contains("second item:"))
{
char[] split = { ':' };
Int32 count = 2;
string str = row.Elements<TableCell>().ElementAt(0).InnerText;
String[] newStr = str.Split(split, count, StringSplitOptions.None);
contents.Add("second item:", newStr[1]);
}
**continues for many more else if statements**
else
{
continue;
}
}
}
return contents;
}
}
I'm new to using XML, so any help would be appreciated!
So whenever I try to append a new line using a StringBuilder, I can't get a new line whatsoever, I tried:
errorMessage.append(System.getProperty("line.separator"));
errorMessage.append(System.getProperty("\n"));
errorMessage.append(System.getProperty("\r\n"));
errorMessage.append(System.getProperty("line.separator"));
basically everything within the first 3 pages of google results, it's so frustrating. I am implementing it in a for loop like this : idk if it helps, but any suggestions are appreciated.
public String getIDs(HashMap<String,List<Integer>> errorMap ){
StringBuilder errorMessage = new StringBuilder();
for (String state:errorMap.keySet()){
List<Integer> listofId = errorMap.get(state);
if (listofId){
StringBuilder listOfIds = new StringBuilder();
for (Integer id :listofId) {
listOfIds.append(id.toString()+' , ')
}
errorMessage.append(state +" Trades: " +listOfIds.toString())
errorMessage.append("\n")
}
}
return errorMessage.toString();
}
Use
errorMessage.append("\n");
Instead of
errorMessage.append(System.getProperty("\n"));
You should directly be using builder.append("\n"). \n is not a property.
Also append method returns builder object itself (Builder pattern). So you can easily do builder.append("\n").append("text1").append("\n").append("text2").....
I have Loader class where I load txt file into BufferedReader from resources and return this field. I use this method but it acts really strange(for me). When I don't put
String str = bufferReader.readLine(); after
bufferReader = new BufferedReader(fileReader);
(in Loader class) than bufferReader in another class is empty, and readLine() returns null. When I write that piece of code in Loader class, I can read each line from txt, except the 1. one which is read in Loader class. Also, I can't read last line if I dont put enter at the end.
public BufferedReader loadFromFileToBufferReader(String fileName) {
ClassLoader classLoader = getClass().getClassLoader();
System.out.print(getClass().getClassLoader().getResource("resources/" + fileName));
File file = new File(classLoader.getResource("resources/" + fileName).getFile());
BufferedReader bufferReader = null;
try (FileReader fileReader = new FileReader(file)) {
bufferReader = new BufferedReader(fileReader);
String str = bufferReader.readLine();
} catch (IOException e) {
System.err.println("Something went terribly wrong with file reading");
}
return bufferReader;
}
and usage:
public Database() {
productsInDatabse = new ArrayList<>();
codesList = new ArrayList<>();
loader = new LoadFromFile();
BufferedReader output = loader.loadFromFileToBufferReader("database.txt");
Product product;
String line;
String[] array;
try {
line = output.readLine();
while (line != null) {
You should paste your code here because it's hard to deduce all the possible causes of this without seeing the code on 100% but I am guessing you have it the same file open at the same time from multiple sources without closing it before from one? Could be literally millions of little things, just telling you how the same error happened to me.
In the applications I'm developing I need to store data for Customer,Products and their Prices.
In order to persist that data I use RMS, but knowing that RMS doesn't support object serializing directly and since that data I read already comes in json format, I store every JSONObject as its string version, like this:
rs = RecordStore.openRecordStore(mRecordStoreName, true);
JSONArray jsArray = new JSONArray(data);
for (int i = 0; i < jsArray.length(); i++) {
JSONObject jsObj = jsArray.getJSONObject(i);
stringJSON = jsObj.toString();
addRecord(stringJSON, rs);
}
The addRecord Method
public int addRecord(String stringJSON, RecordStore rs) throws JSONException,RecordStoreException {
int id = -1;
byte[] raw = stringJSON.getBytes();
id= rs.addRecord(raw, 0, raw.length);
return id;
}
So I have three RecordStores (Customer,Products and their Prices) and for each of them I do the save as shown above to save their corresponding data.
I know this might be a possible to solution, but I'm sure there's gotta be a better implementation. Even more,considering that over those three "tables" I'm going to perform searching, sorting,etc.
In those cases, having to deserialize before proceeding to search or sort doesn't seem a very good idea.
That's why I want to ask you guys. In your experience, how do store custom objects in RMS in way that is easy to work with them later??
I really appreciate all your comments and suggestions.
EDIT
It seems that it's easier to work with records when you define a fixed max length for each field. So here's what I tried:
1) First all, this is the class I use to retrieve the values from the record store:
public class Customer {
public int idCust;
public String name;
public String IDNumber;
public String address;
}
2) This is the code I use to save every jsonObject to the record store:
RecordStore rs = null;
try {
rs = RecordStore.openRecordStore(mRecordStoreName, true);
JSONArray js = new JSONArray(data);
for (int i = 0; i < js.length(); i++) {
JSONObject jsObj = js.getJSONObject(i);
byte[] record = packRecord(jsObj);
rs.addRecord(record, 0, record.length);
}
} finally {
if (rs != null) {
rs.closeRecordStore();
}
}
The packRecord method :
private byte[] packRecord(JSONObject jsonObj) throws IOException, JSONException {
ByteArrayOutputStream raw = new ByteArrayOutputStream();
DataOutputStream out = new DataOutputStream(raw);
out.writeInt(jsonObj.getInt("idCust"));
out.writeUTF(jsonObj.getString("name"));
out.writeUTF(jsonObj.getString("IDNumber"));
out.writeUTF(jsonObj.getString("address"));
return raw.toByteArray();
}
3) This is how I pull all the records from the record store :
RecordStore rs = null;
RecordEnumeration re = null;
try {
rs = RecordStore.openRecordStore(mRecordStoreName, true);
re = rs.enumerateRecords(null, null, false);
while (re.hasNextElement()) {
Customer c;
int idRecord = re.nextRecordId();
byte[] record = rs.getRecord(idRecord);
c = parseRecord(record);
//Do something with the parsed object (Customer)
}
} finally {
if (re != null) {
re.destroy();
}
if (rs != null) {
rs.closeRecordStore();
}
}
The parseRecord Method :
private Customer parseRecord(byte[] record) throws IOException {
Customer cust = new Customer();
ByteArrayInputStream raw = new ByteArrayInputStream(record);
DataInputStream in = new DataInputStream(raw);
cust.idCust = in.readInt();
cust.name = in.readUTF();
cust.IDNumber = in.readUTF();
cust.address = in.readUTF();
return cust;
}
This is how I implemented what Mister Smith suggested(hope it's what he had in mind). However, I'm still not very sure about how to implement the searchs.
I almost forget to mention that before I made theses changes to my code, the size of my RecordStore was 229048 bytes, now it is only 158872 bytes :)
RMS is nothing of the sort of a database. You have to think of it as a record set, where each record is a byte array.
Because of this, it is easier to work with it when you define a fixed max length for each field in the record. For instance, a record could be some info about a player in a game (max level reached, score, player name, etc). You could define the level field as 4 bytes long (int), then a score field of 8 bytes (a long), then the name as a 100 bytes field (string). This is tricky because strings usually will be of variable length, but you would probably like to have a fixed max length for this field, and if some string is shorter than that, you'd use a string terminator char to delimite it. (This example is actually bad because the string is the last field, so it would have been easier to keep it variable length. Just imagine you have several consecutive fields of type string.)
To help you with serialization/deserialization, you can use DataOutputstream and DataInputStream. With these classes you can read/write strings in UTF and they will insert the string delimiters for you. But this means that when you need a field, as you don't know exactly where it is located, you'll have to read the array up to that position first.
The advantage of fixed lengths is that you could later use a RecordFilter and if you wanted to retrieve recors of players that have reached a score greater than 10000, you can look at the "points" field in exactly the same position (an offset of 4 bytes from the start of the byte array).
So it's a tradeoff. Fixed lengths means faster access to fields (faster searches), but potential waste of space. Variable lengths means minimum storage space but slower searches. What is best for your case will depend on the number of records and the kind of searches you need.
You have a good collection of tutorials in the net. Just to name a few:
http://developer.samsung.com/java/technical-docs/Java-ME-Record-Management-System
http://developer.nokia.com/community/wiki/Persistent_Data_in_Java_ME
I have string value like this:
string strRole = "ab=Admin,ca=system,ou=application,role=branduk|ab=Manager,ca=system,ou=application,role=brankdusa|ab=sale,ca=system,ou=application,role=brandAu";
I just need to retrieve role to string array. I wonder if there is the best way to split the string in C# 4.0
string[] arrStrRole = strRole.Split('|').Select .. ??
Basically, I need brandUK, brandUsa, brandAu to string[] arrStrRole.
Thanks.
string[] arrStrRole = strRole.Split('|').Select(r => r.Split(new []{"role="}, StringSplitOptions.None)[1]).ToArray()
results in an string array with three strings:
branduk
brankdusa
brandAu
you can use string[] arrStrRole = strRole.Split('|',','); and this will split according to | and , characters
You can use String.Split in this LINQ query:
var roles = from token in strRole.Split('|')
from part in token.Split(',')
where part.Split('=')[0] == "role"
select part.Split('=')[1];
Note that this is yet prone to error and requires the data always to have this format. I mention it because you've started with Split('|').Select.... You can also use nested loops.
If you need it as String[] you just need to call ToArray:
String[] result = roles.ToArray();
I would go with Regex rather than splitting string. In combination with your intended Select solution, it could look like this:
var roles = Regex.Matches(strRole, #"role=(\w+)")
.Cast<Match>()
.Select(x => x.Groups[1].Value).ToArray();
You could use an extension like this which would allow you to test it easily.
public static string[] ParseRolesIntoList(this string csvGiven)
{
var list = new List<string>();
if (csvGiven == null) return null;
var csv = csvGiven.Split(',');
foreach (var s in csv)
{
if (string.IsNullOrEmpty(s)) continue;
if(!s.StartsWith("role")) continue;
var upperBound = s.IndexOf("|");
if (upperBound <= 0) upperBound = s.Length;
var role = s.Substring(s.IndexOf("=") + 1,
upperBound - s.IndexOf("=") - 1);
list.Add(role);
}
return list.ToArray();
}
Test below found brankdusa typo in your example. Some of the other answers would not deal with brandAu as it matches slightly differently. Try running this test against them if you like
[Test]
public void Should_parse_into_roles()
{
//GIVEN
const string strRole = "ab=Admin,ca=system,ou=application,role=branduk|ab=Manager,ca=system,ou=application,role=brankdusa|ab=sale,ca=system,ou=application,role=brandAu";
//WHEN
var roles = strRole.ParseRolesIntoList();
//THEN
Assert.That(roles.Length, Is.EqualTo(3));
Assert.That(roles[0], Is.EqualTo("branduk"));
Assert.That(roles[1], Is.EqualTo("brankdusa"));
Assert.That(roles[2], Is.EqualTo("brandAu"));
}
This gives an array of the 3 values.
void Main()
{
string strRole = "ab=Admin,ca=system,ou=application,role=branduk|ab=Manager,ca=system,ou=application,role=brankdusa|ab=sale,ca=system,ou=application,role=brandAu";
var arrStrRole = strRole.Split('|',',')
.Where(a => a.Split('=')[0] == "role")
.Select(b => b.Split('=')[1]);
arrStrRole.Dump();
}