I need to find all 4,5,6 letter words in a string of letters. When we find each for letter word, we are then supposed asked to check if the word is in the English dictionary.
The problem I am facing is that I am not sure how I can make java find all 4,5,6 letter words?
The example they gave us is like this:
String letter = "fourgooddogsswam";
int wordSize = 4;
Then the words are:
four
ourg
urgo
rgoo
good
oodd
oddo
ddog
dogs
ogss
gssw
sswa
swam
In reality, the only words are four, good, dogs, swam.
Again, I am wondering how to make a loop or something of that nature in order to find all of the four letter words. Any help or tips are highly appreciated.
Thank you.
This is a pretty simple algorithm and if you are taking classes of basic programing is better way take time to think about and learn than use forums to answer your homework
for(int i = 0; i < letter.length()-4;i++){
fourLetter = letter.substring(i,i+4);
//... do whatever you want
}
First You need to split the string of size 4.By using below code you will get array of String having length 4.
List<String> elementList = new ArrayList<String>();
for(int i = 0; i < letter.length()-4;i++){
fourLetter = letter.substring(i,i+4);
elementList.add(fourLetter);
}
Then you need to read the dictionary words from file and insert into set<String>.
Then you can convert String array to List and iterate the list and check of set.contains(listelement).
Related
I am trying to split a word into its individual letters.
I tried both String.split("") and String.split("|") however when I split a word it is creating a extra empty element.
Example:
word = "word";
int n = word.length();
Log.i("20",Integer.toString(n));
String[] letters = word.split("|");
Log.i("25",Integer.toString(letters.length));
The output in the Android Monitor is:
07-21 15:50:23.084 5711-5711/com.strizhevskiy.movetester I/20: 4
07-21 15:50:23.085 5711-5711/com.strizhevskiy.movetester I/25: 5
I put the individual letters into TextView blocks and I can actually see an extra empty TextView.
When I test these methods in my regular Java it outputs the expected answer: 4.
I am almost tempted to think this is an actual bug in Android's implementation of the method.
I am thinking you want to do this:
public Character[] toCharacterArray( String s ) {
if ( s == null ) {
return null;
}
int len = s.length();
Character[] array = new Character[len];
for (int i = 0; i < len ; i++) {
array[i] = new Character(s.charAt(i));
}
return array;
}
Instead of splitting a word without delimiters?
I hope this helps!
It's hard to say if it's bug or expected behavior, because what are you doing doesn't make sense. You are trying to split string with logical OR (split is waiting for Regular expression, not just a string), so as result it could be different result in Android comparing with normal java, and I don't see there any issue.
Anyway, there is many ways to achieve what you want in a normal way, e.g. just iterating over word by each char in a cycle or just use toCharArray String's method.
Thank you for the suggestions. My current work-around is to use a mock array and copying over into a fresh array using System.arraycopy().
String[] mockLetters = word.split("");
int n = word.length();
String[] letters = new String[n];
System.arraycopy(mockLetters,1,letters,0,n);
I appreciate the suggestions to use toCharArray(). However, these letters then get put into TextViews and TextView doesnt seem to accept char. I could, of coarse, make it work but I've decided to stick with what I currently have.
Tom, in a comment to my question, answered my underlying issue:
Why String.split() worked differently in Android than it does in Java?
Apparently the rules for String.split() changed with Java 8.
Try passing a 0 as the limit per the documentation below so that the trailing spaces are discarded.
String[] split (String regex,
int limit)
If n is zero then the pattern will be applied as many times as possible, the array can have any length, and trailing empty strings will be discarded.
I have a list of keywords in a List and I have data coming from some source which will be a list too.
I would like to find if any of keywords exists in the data list, if yes add those keywords to another target list.
E.g.
Keywords list = FIRSTNAME, LASTNAME, CURRENCY & FUND
Data list = HUSBANDFIRSTNAME, HUSBANDLASTNAME, WIFEFIRSTNAME, SOURCECURRENCY & CURRENCYRATE.
From above example, I would like to make a target list with keywords FIRSTNAME, LASTNAME & CURRENCY, however FUND should not come as it doesn't exists in the data list.
I have a solution below that works by using two for loops (one inside another) and check with String contains method, but I would like to avoid two loops, especially one inside another.
for (int i=0; i<dataList.size();i++) {
for (int j=0; j<keywordsList.size();j++) {
if (dataList.get(i).contains(keywordsList.get(j))) {
targetSet.add(keywordsList.get(j));
break;
}
}
}
Is there any other alternate solution for my problem?
Here's a one loop approach using regex. You construct a pattern using your keywords, and then iterate through your dataList and see if you can find a match.
public static void main(String[] args) throws Exception {
List<String> keywords = new ArrayList(Arrays.asList("FIRSTNAME", "LASTNAME", "CURRENCY", "FUND"));
List<String> dataList = new ArrayList(Arrays.asList("HUSBANDFIRSTNAME", "HUSBANDLASTNAME", "WIFEFIRSTNAME", "SOURCECURRENCY", "CURRENCYRATE"));
Set<String> targetSet = new HashSet();
String pattern = String.join("|", keywords);
for (String data : dataList) {
Matcher matcher = Pattern.compile(pattern).matcher(data);
if (matcher.find()) {
targetSet.add(matcher.group());
}
}
System.out.println(targetSet);
}
Results:
[CURRENCY, LASTNAME, FIRSTNAME]
Try Aho–Corasick algorithm. This algorithm can get the count of appearance of every keyword in the data (You just need whether it appeared or not).
The Complexity is O(Sum(Length(Keyword)) + Length(Data) + Count(number of match)).
Here is the wiki-page:
In computer science, the Aho–Corasick algorithm is a string searching
algorithm invented by Alfred V. Aho and Margaret J. Corasick. It is
a kind of dictionary-matching algorithm that locates elements of a
finite set of strings (the "dictionary") within an input text. It
matches all patterns simultaneously. The complexity of the algorithm
is linear in the length of the patterns plus the length of the
searched text plus the number of output matches.
I implemented it(about 200 lines) years ago for similar case, and it works well.
If you just care keyword appeared or not, you can modify that algorithm for your case with a better complexity:
O(Sum(Length(Keyword)) + Length(Data)).
You can find implementation of that algorithm from internet everywhere but I think it's good for you to understand that algorithm and implement it by yourself.
EDIT:
I think you want to eliminate two-loops, so we need find all keywords in one loop. We call it Set Match Problem that a set of patterns(keywords) to match a text(data). You want to solve Set Match Problem, then you should choose Aho–Corasick algorithm which is particularly designed for that case. In that way, we will get one loop solution:
for (int i=0; i < dataList.size(); i++) {
targetSet.addAll(Ac.run(keywordsList));
}
You can find a implementation from here.
All that I am doing in my project is taking two values(that I am reading from two different excel files) and checking how similar they are.! I tried using the pattern and matcher classes which works perfectly fine when both the words are exactly the same (as in organisation and organisation/s). In my data I have say something like (employee and employment), I just need "employ" as the common string between the two, in which case..pattern and matches fails.! I am stuck with this since a week.I have about 700 rows in the first excel file and about 9000 in the other. Each cell value that I am reading into the program using java, I am storing them in two separate variables. Next, i tried using 4 for loops to match word by word and character by character to find only those characters that match between the two.I have pasted the coded for the for loop implementation. Four for loops are like driving me nuts.! Any help in completing this would be greatly appreciated.
String str1 = "Cover for employees of the company";
String str2 = "Employment Agencies ";
String str,strfinal;
String[] count1 = str1.split("\\s+");
String[] count2 = str2.split("\\s+");
char[] count11 = str1.toCharArray();
char[] count22 = str2.toCharArray();
for(int i=0;i<count1.length;i++)
{
for(int j=0;j<count2.length;j++)
{
for(int m=0;m<count1[i].length();m++)
{
for(int n=0;n<count2[j].length();n++)
{
if(count11[m]==count22[n])
{
// please look at the logic that I am looking for to implement
}
}
}
}
}
Expected output: employ
one more concept that I am trying to implement (in order to make my program more efficient) is..
cover ----(compared with) employment. First character itself does not match.Implies go to the next word in the second string. Once all words in the second string are traversed and checked for, go to the next word in the first string and compare this word with all the words in the second string.
Okay.. so this is what I am looking for right now.. Any help will be greatly appreciated.
Thanks!
I am currently working on a project with a lot of different componenets but one of them is really stumping me. I have to wrte a mutltidimensional array that stores a list of names. The names are are already in a single dimensional array and have been sorted into alphabetical order. For the multidimentioal array I need to store all the names that begin with A in the first set, all the names that begin with B in the second, and so on. I know I can use the ASCII value of the charachters to keep track of the first postion by subrtacting 65 from the value of the letter in the first position of the name and setting that equal to i for array[i] but I don't really know how to store the name after that. Needless to say, I'm really confused and can hardly even say what it is I need. Any help at all is appreciated I haven't written any code yet because I dont't know what to write
I would use a ArrayList as the second dimension of the array. That way you can arbitrarily add any number of strings. Here is a sample to give you some ideas
ArrayList<String>[] nameList = new ArrayList[25];
for(int i =0; i < nameList.length; i++){
nameList[i] = new ArrayList<String>();
}
String[] names = {"Ali","Joe","Sue","Jane"};
for(int i = 0; i < names.length;i++){
int firstLetterCharacterCode = names[i].charAt(0) - 65;
nameList[firstLetterCharacterCode].add(names[i]);
}
for(int i =0; i < nameList.length;i++){
for(String name : nameList[i]){
System.out.println(name);
}
}
If your feeling bold you can look into maps. It would make accessing a particular set of names list more elegant since you could use the letter of the key.
I'm working on a program for a class and was wondering if someone could point me in the right direction. I've worked with Java before, but it's been a while and I'm really rusty. The purpose of this program is to prompt a user to enter a phone number represented by letters (for example CALL HOME would be 225-5466), the program is then to display the phone number based on the letters entered.
We are supposed to store the letters entered by the user into an array and then convert those letters into the actual phone number. Here's what I'm getting stuck on at the moment, I've only worked with arrays consisting of numbers so am not sure how to set this one up. I'm assuming that each index would be one letter, but how would I break the string entered by the user down into individual char characters?
I'm still in the process of thinking through how this program should work and putting it on paper so haven't actually started coding yet, so I apologize for not having any code to share. But this is what I'm thinking would need to happen once the letter representation of the phone numbers were placed in the array:
Declare variables for each letter, like
int a = 1
int b = 1
int c = 1
int d = 2
etc. Or is there a more efficient way to do that? Then use if statements for each index like,
if [0] == a || b || c
[0] = 1
if [0] == d || e || f
[0] = 2
and so on. Like I said, I'm really rusty and am just trying to think my way through this right now before just throwing code at the screen haha. Any pointers would be much appreciated.
Just use String#toCharArray:
char[] characters = string.toCharArray();
You can then get the individual characters from a string.
You could use a series of if statements to see what characters map to what number. But there are more-elegant approaches. I am not sure if you have used Map<K, V>, but you could set up a Map<String, Integer> that maps a letter to its integer representation. Then you'd simply have to iterate over the characters in the string and look up their value.
Since this is homework, this is about as much information that I think is appropriate. Using what I have given you, you should be able to come up with an algorithm. Just start writing the code even if you don't know what the end result will look like. This will give you the following advantages:
Give you a clearer idea of the problem.
Will familiarize you with the problem-space.
Will help you visualize and understand your problem and the algorithm.
What you can do is to create a 2 dimensional array and methods to check the input against it. For example you can do the following:
Create an array numbers of length 10. Each index corresponds to a number you have to call.
Now each entry of the numbers array is an array of chars. So in the end you have something like this :
numbers = [['w/e you want for 0'],['a','b','c'],['d','e','f'], ['g','h','i'], ... etc ]
When you parse the input string you compare each character with a method like this:
private int letterToNumber(char c){
for(i = 0; i < numbers.length; i++)
if(contains(numbers[i], c) return i;
}
and your contains() method should be something like that
private boolean contains(char[] chars, char c){
for(char x : chars)
return(x == c)? true; false;
}