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Retrieve String from values in HashMap at a specific occurrence of special character

So I'm trying retrieve specific substrings in values in a Hashmap constructed like this..
HashMap<ID, "Home > Recipe > Main Dish > Chicken > Chicken Breasts">
Which is passed from a different method that returns a HashMap
In above example, I need to retrieve Chicken.
Thus far, I have..
public static ArrayList<String> generalize() {
HashMap<String, String> items = new HashMap<>();
ArrayList<String> cats = new ArrayList<>();
items = RecSys.readInItemProfile("PATH", 0, 1);
for(String w : items.values()) {
cats.add(w);
}
for(String w : cats) {
int e = w.indexOf('>', 1 + w.indexOf('>', 1 + w.indexOf('>')));
String k = w.substring(e+1);
System.out.print(k);
e = 0;
}
System.out.println("k" + cats);
return cats;
}
Where I try to nullify String e for each iteration (I know it's redundant but it was just to test).
In my dataset, the first k-v pair is
3880=Home  >  Recipes  >  Main Dish  >  Pasta,
My output is
Pasta
Which is ok. If there are more than 3x ">", it'll return all following categories. Optimally it wouldn't do that, but it's ok if it does. However, further down the line, it (seemingly) randomly returns
Home > Recipe
Along with the rest of the data...
This happens at the 6th loop, I believe.
Any help is greatly appreciated..
Edit:
To clarify, I have a .csv file containing 3 columns, whereas 2 are used in this function (ID and Category). These are passed to this function by a read method in another class.
What I need to do is extract a generalized description of each category, which in all cases is the third instance of category specification (that is, always between the third and fourth ">" in every k-v pair).
My idea was to simply put all values in an arraylist, and for every value extract a string from between the third and fourth ">".

I recommend using the following map:
Map<Integer, List> map = new HashMap<>();
String[] vals = new String[] { "HomeRecipe", "Main Dish", "Chicken",
"Chicken Breasts" };
map.put(1, Arrays.asList(vals));
Then, if you need to find a given value in your original string using an ID, you can simply call ArrayList#get() at a certain position. If you don't care at all about order, then a map of integers to sets might make more sense here.

If you can. change your data structure to a HashMap<Integer, List<String>> or HashMap<Integer, String[]>. It's better to store the categories (by cats you mean categories right?) in a collection instead of a string.
Then you can easily get the third item.
If this is not possible. You need to do some debugging. Start by printing every input and output pair and find out which input caused the unexpected output. Your indexOf method seems to work at first glance.
Alternatively, try this regex method:
String k = cats.replaceAll("(?:[^>]+\\s*>\\s*){3}([^>]+).*", "$1");
System.out.println(k);
The regex basically looks for a xxx > yyy > zzz > aaa ... pattern and replaces that pattern with aaa (whatever that is in the original string).

Access to the key-value pair of a Map with one element in Java

A method of mine returns a Map<A,B>. In some clearly identified cases, the map only contains one key-value pair, effectively only being a wrapper for the two objects.
Is there an efficient / elegant / clear way to access both the key and the value? It seems overkill to iterate over the one-element entry set. I'm looking for somehing that would lower the brain power required for people who will maintain this, along the lines of:
(...)
// Only one result.
else {
A leKey = map.getKey(whicheverYouWantThereIsOnlyOne); // Is there something like this?
B leValue = map.get(leKey); // This actually exists. Any Daft Punk reference was non-intentional.
}
Edit: I ended up going with #akoskm solution's below. In the end, the only satisfying way of doing this without iteration was with a TreeMap, and the overhead made that unreasonable.
It turns out there is not always a silver bullet, especially as this would be a very small rabbit to kill with it.

If you need both key/value then try something like this:
Entry<Long, AccessPermission> onlyEntry = map.entrySet().iterator().next();
onlyEntry.getKey();
onlyEntry.getValue();

You can use TreeMap or ConcurrentSkipListMap.
TreeMap<String, String> myMap = new TreeMap<String, String>();
String firstKey = myMap.firstEntry().getKey();
String firstValue = myMap.firstEntry().getValue();
Another way to use this:
String firstKey = myMap.firstKey();
String firstValue = myMap.get(myMap.firstKey());
This can work as an alternate solution.

There is a method called keySet() to get set of keys. read this thread.
else {
A leKey=map.keySet().iterator().next();
B leValue; = map.get(leKey); // This actually exists. Any Daft Punk reference was non-intentional.
}

Using for-each loop and var :
for(var entry : map.entrySet()){
A key = entry.getKey();
B value = entry.getValue();
}

Foreach Key/Value pair issue

I'm trying to convert a PHP script into a Java one but coming across a few issues on a foreach loop. In the PHP script I have a foreach that takes the key:value pair and based off this does a str_replace.
foreach ($pValues AS $vKey => $vValue)
$vString = str_replace("{".$vKey."}", "'".$vValue."'", $vString);
I tried replicating this in Java without success. I need to get the key from the array to use in the string replace function, but can't find out where or if it's possible to get the key name from the array passed in.
Is this the right way or am I completely off? Should I be using the ImmutablePair method?
for (String vKey : pValues)
// String replace
Here's hoping there is an easy way to get the key:value pair in Java.

This can be acheived by using Map as data structure and then using entryset for iterating over it.
Map<K,V> entries= new HashMap<>();
for(Entry<K,V> entry : entries.entrySet()){
// you can get key by entry.getKey() and value by entry.getValue()
// or set new value by entry.setValue(V value)
}

That is not possible with a simple foreach-loop in Java.
If pValues is an array, you could use a simple for-loop:
for (int i = 0; i < pValues.length; i++)
// String replace
If pValues is a Map, you can iterate through it like this:
for (Key key : map.keySet())
string.replace(key, map.get(key));

Group Totals
Have the function GroupTotals(strArr) read in the strArr parameter containing key:value pairs where the key is a string and the value is an integer. Your program should return a string with new key:value pairs separated by a comma such that each key appears only once with the total values summed up.
For example: if strArr is ["B:-1", "A:1", "B:3", "A:5"] then your program should return the string A:6,B:2.
Your final output string should return the keys in alphabetical order. Exclude keys that have a value of 0 after being summed up.

Thanks all for the help and advice, I've managed to duplicate the function in Java using Map.
if (pValues != null)
{
Set vSet = pValues.entrySet();
Iterator vIt = vSet.iterator();
while(vIt.hasNext())
{
Map.Entry m =(Map.Entry)vIt.next();
vSQL = vSQL.replace("{" + (String)m.getKey() + "}", "'" + (String)m.getValue() + "'");
vSQL = vSQL.replace("[" + (String)m.getKey() +"]", (String)m.getValue());
}
}

Unsure how this piece of code is doing what it does… .getDescribe()

I'm relatively new to Apex and Java.
Could someone possibly explain this snippet of code?
Map<String, SObjectField> m = Opportunity.SObjectType.getDescribe().fields.getMap();
for (String name : m.keySet()) {
DescribeFieldResult r = m.get(name).getDescribe();
System.debug(r);
}
I know it's getting the Describe information for each field on the Opportunity object, but could someone explain, line by line, how it's doing it?
Cheers!

This is about as basic as it gets when you need to enumerate a map:
Line 1 gets the map, and stores it in variable m
Line 2 iterates over the keys of the map m, using name variable for the value of the key in this iteration
Line 3 gets the item from the map m using name for the key, and calls getDescribe
Line 4 passes the result to System.debug
Line 5 closes the loop
However, this is not the best way of iterating the values, though: a simpler approach would be as follows:
Map<String, SObjectField> m = Opportunity.SObjectType.getDescribe().fields.getMap();
for (SObjectField val : m.values()) {
System.debug(val.getDescribe());
}
For completeness, if you would like to iterate both keys and values, iterate entrySet, like this:
Map<String, SObjectField> m = Opportunity.SObjectType.getDescribe().fields.getMap();
for (Map.Entry<String,SObjectField> e : m.entrySet()) {
// e.getKey() produces the key
// e.getValue() produces its associated value
}
Iterating keys and then retrieving the values in a separate call to get is inefficient.

I have a query in mongodb and the reference key's are in hashmap list , I need to process a simple query using java in mongodb

mongodb query is db.test.find({"col1":{"$ne":""}}).count(), I have tried many sources to find the solution, the "col1" must be populated from list array, please help me
I have pasted a part of my code
`
List<String> likey = new ArrayList<String>();
for (DBObject o : out.results())
{
likey.add(o.get("_id").toString());
}
Iterator<String>itkey = likey.iterator();
DBCursor cursor ;
//cursor = table.find();
HashMap<String, String> hashmap = new HashMap<String, String>();
while (itkey.hasNext())
{
System.out.println((String)itkey.next());
String keys = itkey.next().toString();
//System.out.println("keys --> "+keys);
String nullvalue = "";
Boolean listone = table.distinct(keys).contains(nullvalue);
hashmap.put(keys, listone.toString());
//System.out.println("distinct --> "+keys+" "+listone);
//System.out.println("proper str --- >"+ '"'+keys+'"');
}
Iterator<String> keyIterator = hashmap.keySet().iterator();
Iterator<String> valueIterator = hashmap.values().iterator();
while (keyIterator.hasNext()) {
//System.out.println("key: " + keyIterator.next());
while (valueIterator.hasNext()) {
//System.out.println("value: " + valueIterator.next());
//System.out.println("Key: " + keyIterator.next() +""+"value: "+valueIterator.next());
String hashkey = valueIterator.next();
}
}
`

When you post code, it helps if you indent it, so it is more readable. As I mentioned to you on another forum, you need to go back and review the Java collection classes, since you have multiple usage errors in the above code.
Here are a few things you need to do to clean up your code:
1) You don't need to use the itkey iterator. Instead, use:
for (String key : likey)
and get rid of all the itkey.next calls. Your current code only processes every second element of the List. The other ones are printed out.
2) Your HashMap will map a key to a Boolean. Is that what you want? You said you want to count the number of non-zero values for the key. So, the line:
Boolean listone = table.distinct(keys).contains(nullvalue);
is almost certainly in error.
3) When you iterate over the HashMap, you don't need the valueIterator. Instead, get the key (either from the keyIterator, or a variable you define using the simpler iterator syntax above), then use the key to get the matching value using hashmap.get(key).
This will not make your code work, but it will clean it up somewhat - at the moment it is difficult to understand what you are intending it to do.