I am trying to prevent name duplicates in a List, but with no luck so far.I have a list of entries and each entry has a name (e.g. entries: "file", "file1", "someFile", "anotherFile"). Whenever I create new entry I add it to the entry List. But I don't want to add new entry with the same name.I have a file that I just created (e.g. name: "file"). How do I find all name duplicates and make it something like this at the end: "file2"?
Sorry if the question is a bit vague.
I tried to use LINQ and Regex, but I'm kind of new to those things so not sure what I'm doing..
According to what you have posted in question a simple program with if-else conditions could solve your problem:
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
public class Program
{
public static void Main()
{
string[] entries = new []{"file", "file1", "someFile", "anotherFile", "file", "someFile", "file"};
List<string> curatedEntries = new List<string>();
foreach(string e in entries)
{
int index = 0;
string entry = e;
Check:
if(CheckExists(curatedEntries, entry)){
index++;
entry = e + index;
goto Check;
}
curatedEntries.Add(entry);
}
curatedEntries.ForEach(x=>Console.WriteLine(x));
}
public static bool CheckExists(List<string> lst,string e)
{
return lst.Any(x=>x.Equals(e));
}
}
Here's fiddle: https://dotnetfiddle.net/fdSClH
Related
I have the following:
IEnumerable<Personel> personel= page.Retrieve<Personel>....
Then I have List which contains only personelIDs
List<int> personelIDs....
I need to retrived all 'personels' from the IEnumerable and assign it into a new List which matches the personelIDs from 'personelIDs ' list.
I can do it my iterating and having verify the IDs and if they're equal assign it into another List,
but is there a short here where I can retrieve it without iterating or having multiple lines of code?
Basically Is there a way on how to shortened this
List<int> pIds = ....// contains only specific personellID's
IEnumerable personelIEn = // contains Personel data like personel IDs, name..etc
List<Personel> personel = personelIEn.ToList();
List<Personel> personelByTag = new List<Personel>();
foreach (Personel b in personel ) {
if (pIds.Contains(b.DocumentID)) {
personelByTag .Add(b);
}
}
return personelByTag ;
basically I'm trying to find ways how to shortened the above code
You can use a predicate:
public List<Personel> search(String documentId, List<Personel> list)
{
Predicate<Personel> predicate = (Personel personel) => (personel.Id== documentId);
return list.FindAll(predicate);
}
Could that help?
Suppose I have two class:
class Key {
private Integer id;
private String key;
}
class Value {
private Integer id;
private Integer key_id;
private String value;
}
Now I fill the first list as follows:
List<Key> keys = new ArrayLisy<>();
keys.add(new Key(1, "Name"));
keys.add(new Key(2, "Surname"));
keys.add(new Key(3, "Address"));
And the second one:
List<Value> values = new ArrayLisy<>();
values.add(new Value(1, 1, "Mark"));
values.add(new Value(2, 3, "Fifth Avenue"));
values.add(new Value(3, 2, "Fischer"));
Can you please tell me how can I rewrite the follow code:
for (Key k : keys) {
for (Value v : values) {
if (k.getId().equals(v.getKey_Id())) {
map.put(k.getKey(), v.getValue());
break;
}
}
}
Using Lambdas?
Thank you!
‐------UPDATE-------
Yes sure it works, I forget "using Lambdas" on the first post (now I added). I would like to rewrite the two nested for cicle with Lamdas.
Here is how you would do it using streams.
stream the keylist
stream an index for indexing the value list
filter matching ids
package the key instance key and the value instance value into a SimpleEntry.
then add that to a map.
Map<String, String> results = keys.stream()
.flatMap(k -> IntStream.range(0, values.size())
.filter(i -> k.getId() == values.get(i).getKey_id())
.mapToObj(i -> new AbstractMap.SimpleEntry<>(
k.getKey(), values.get(i).getValue())))
.collect(Collectors.toMap(Entry::getKey, Entry::getValue));
results.entrySet().forEach(System.out::println);
prints
Address=Fifth Avenue
Surname=Fischer
Name=Mark
Imo, your way is much clearer and easier to understand. Streams/w lambdas or method references are not always the best approach.
A hybrid approach might also be considered.
allocate a map.
iterate over the keys.
stream the values trying to find a match on key_id's and return first one found.
The value was found (isPresent) add to map.
Map<String,String> map = new HashMap<>();
for (Key k : keys) {
Optional<Value> opt = values.stream()
.filter(v -> k.getId() == v.getKey_id())
.findFirst();
if (opt.isPresent()) {
map.put(k.getKey(), opt.get().getValue());
}
}
Basically, I'm trying to return a collection of strings in Java.
But...
each string must be unique because they're all the names of ".db" files in current folder, so I thought this collection should be LinkedHashSet.
The elements (filenames) must maintain the exact same order, so I can choose one of them by it's order number in the collection.
My main routine will show this collection in a GUI component (maybe a JList) for the user to choose one of them (without the .db extension).
I'm totally newbie (as you can see), so if you think there are better options than LinkedHashSet please tell me.
Also, how can I grab this collection in the main class?
What I've got so far:
public Set GetDBFilesList() {
//returns ORDERED collection of UNIQUE strings with db filenames
LinkedHashSet a = new LinkedHashSet();
FilenameFilter dbFilter = (File file, String name) -> {
return name.toLowerCase().endsWith(".db");
};
String dirPath = "";
File dir = new File(dirPath);
File[] files = dir.listFiles(dbFilter);
if (files.length > 0) {
for (File aFile : files) {
a.add(aFile.getName());
}
}
return a;
}
You want an ordered and unique collection - LinkedHashSet is a good choice.
Some comments on your methode:
Your should use Generics f.e.: LinkedHashSet<File> or LinkedHashSet<String>
The check for files.length is unnecessary, but you could check for null if the path is not a directory or an I/O error occured
You should name your variables properly: a is not a good name
Your methode can be static - maybe in a static helper class?
The Set.add methode returns true or false if the item was added or not, you should check that just in case
Putting all together:
//Your Main class
public class Main
{
public static void main(String[] args)
{
File dir = new File("");
Collection<File> dbFiles = DbFileManager.getDatabaseFiles(dir);
}
}
//Your DB File Reader Logic
public class DbFileManager
{
public static Collection<File> getDatabaseFiles(File directory)
{
Collection<File> dbFiles = new LinkedHashSet<>();
//filter code etc.
boolean success = dbFiles.addAll(directory.listFiles(filter));
//Check if everthing was added
return dbFiles;
}
}
Is there a way of dynamically building a cypher query using spring data neo4j?
I have a cypher query that filters my entities similar to this one:
#Query("MATCH (n:Product) WHERE n.name IN {0} return n")
findProductsWithNames(List<String> names);
#Query("MATCH (n:Product) return n")
findProductsWithNames();
When the names list is empty or null i just want to return all products. Therefore my service impl. checks the names array and calls the correct repository method. The given example is looks clean but it really gets ugly once the cypher statements are more complex and the code starts to repeat itself.
You can create your own dynamic Cypher queries and use Neo4jOperations to execute them. Here is it an example (with a query different from your OP) that I think can ilustrate how to do that:
#Autowired
Neo4jOperations template;
public User findBySocialUser(String providerId, String providerUserId) {
String query = "MATCH (n:SocialUser{providerId:{providerId}, providerUserId:{providerUserId}})<-[:HAS]-(user) RETURN user";
final Map<String, Object> paramsMap = ImmutableMap.<String, Object>builder().
put("providerId", providerId).
put("providerUserId", providerUserId).
build();
Map<String, Object> result = template.query(query, paramsMap).singleOrNull();
return (result == null) ? null : (User) template.getDefaultConverter().convert(result.get("user"), User.class);
}
Hope it helps
Handling paging is also possible this way:
#Test
#SuppressWarnings("unchecked")
public void testQueryBuilding() {
String query = "MATCH (n:Product) return n";
Result<Map<String, Object>> result = neo4jTemplate.query(query, Collections.emptyMap());
for (Map<String, Object> r : result.slice(1, 3)) {
Product product = (Product) neo4jTemplate.getDefaultConverter().convert(r.get("n"), Product.class);
System.out.println(product.getUuid());
}
}
im trying to read a large file, so i thought that instead of looping with an array i decided to use a list, but I'm having some difficulties with searching a line which contains a word that needs to be searched for. Here is my code
public List<string> AWfile = new List<string>();
private void button1_Click(object sender, EventArgs e)
{
if (File.Exists(#"C:\DataFolder\file.txt"))
{
using (StreamReader r = new StreamReader(#"C:\DataFolder\file.txt"))
{
string line;
while ((line = r.ReadLine()) != null)
{
AWfile.Add(line); label1.Text = "ListWritten!"; label1.BackColor = Color.Green;
}
}
}
}
private void button2_Click(object sender, EventArgs e)
{
int linen = AWfile.IndexOf("A102");
label2.Text = Convert.ToString(linen);
}
So my question is if there is any way to search just for a part of a word in a list instead of the whole string, because that's the only way the .IndexOf returns me anything at all.
You can try something like:
var result = list.Select(x => x.Contains("hello")).ToList()
This will result in a list with all the elements in the list which contains "hello".
And if you want to do something only with this elements:
list.Select(x => x.Contains("hello")).ToList().ForEach(x => DoSomething(x));
I hope this helps
If I understand your question correctly... you are reading in a file and adding each line to a list. Then you want to check if any of those lines contain part of a word.
One way of doing this would be to do a foreach loop over each of the lines in your list and checking if the line contains the partial word.
Something like:
foreach(var line in AWFile)
{
if(line.Contains("PartialWordWeWant"))
{
// Do something with the line that contains the word we are looking for
}
}