How to Compare Contents of Two Files

[CodeTilYaDrop]

Does anyone know how to compare contents of two ArrayLists? I want to compare them to see if they match up. Do you have an example or could you point me in the right direction. I know I need to loop through it with an if statement a for loop somehow or both, but I am not sure how. thanks for any help you can provide-

[r035198x]

Does anyone know how to compare contents of two ArrayLists? I want to compare them to see if they match up. Do you have an example or could you point me in the right direction. I know I need to loop through it with an if statement a for loop somehow or both, but I am not sure how. thanks for any help you can provide-

The objects in the ArrayList are Comparable, right?
When you say you want to see if they "match up" you mean if they contain equal objects at the same locations, right?

Then a simple loop going through the ArrayLists should do it.

[CodeTilYaDrop]

It is not that simple. I am trying to compare two separate documents, and find where the changes were made. I want to go through some type of loop to find the changes made on one comparred to the other. The contents may be moved all around.

[r035198x]

It is not that simple. I am trying to compare two separate documents, and find where the changes were made. I want to go through some type of loop to find the changes made on one comparred to the other. The contents may be moved all around.

That is not what you said in your original post is it? So these documents are what type? .txt, .odt, e.t.c?

[CodeTilYaDrop]

They are both text files.

[CodeTilYaDrop]

They are both text files.

I put them both in an ArrayList though.

[r035198x]

I put them both in an ArrayList though.

What kind of changes are you trying to look for.
It may be better to read the files into two StringBuilders. Open the specs for the StringBuilder class and see what can be done on it.

[CodeTilYaDrop]

I just want to know the word changes of the two documents. Could I use the indexOf in a loop to notice the changes?

[CodeTilYaDrop]

What about the contains method. What do you think?

[r035198x]

If you use contains, you would be testing to see if it contains what?
To test for word differences, just look word by word in the files and see if the words are the same.

OK Suppose you have the file initially as

this
was the 
file before

Then later it becomes

was this
the
file before

What should the program do?

[CodeTilYaDrop]

I guess I just want to see the word differences for now. Do you know an looping algorithm for this??

[r035198x]

I guess I just want to see the word differences for now. Do you know an looping algorithm for this??

You haven't answered my question yet.
The answer determines what (if any) kind of a loop you need.

[CodeTilYaDrop]

I am not sure exactly what I need when you put it this way. I will take a look at what I am doing, and see if I can clarify my questions. thanks for trying to help me-

[JosAH]

Have a look at the diff algorithm.
It implements the LCS (Longest Common Substring) algorithm in order to find
the minimal adjustments (inserts, updates, deletes) needed to transform one
text to the other text.

kind regards,

Jos

[CodeTilYaDrop]

You all are great helpers! I really appreciate it!

Can I ask you about one more thing. I was reading about an inner and outer loop to compare items in arrays. Do you know where to find the algorithm for this, too? This might help me too!