Page 3 - Filtering Strings

Ahh, I will do some more later. It sounds like I have been using the indexOf method completely wrong.

The indexOf() method would find the location of "cat". Then look at the character before it and the character after it. Their identity would say if "cat" was a word or was a subpart of another larger word.

I still don't get it. So I get various numbers that relate to index positions:

cat is happy

where icat

hi cat whats up

turn cat


....0, 7, 3, 5, etc...I don't understand what that does for me. I can get the length but...I don't see how that helps me any either. Yes, it should be three, but it will be that way with cat or catacomb.

If you look at second example with the icat.
You got the index of 7, what result will you get if you look at the character in front of c (index-1)? what does this tell related/compared to what is a valid delimiter?

charAt(6) = i



It tells me that every possible character is a possibility before and after the word cat. Given words like catacomb, I don't know how to tell with them...This is probably where I am going wrong.

Do you know what the term "delimiter" means?
Most words we type are delimited by spaces.
Other delimiters are the beginning of a sentence.
Other delimiters for words are comma and period.
If a String is delimited by any of these characters then it is a word. If it has other delimiters then it is NOT a word.
Your search is for words like cat not category. In category, cat has a following delimiter of e which makes the cat in category not a word.

Hardly, we never went over them in class, although there was a brief mention of them in Chapter 2. I messed around with them, but they didn't make a lot of sense to me. Should I be using a delimiter in my program?

If I use cat as delimiter, it will cutoff the rest of the input from wherever cat ends up getting typed.

The delimiters I have been talking about are single characters that mark the ends of a String to identify words. The String "cat" would not be called a delimiter.
In the String: "xHerex" the character x is the delimiter for the word: Here

The delimiter I am talking has nothing to do with any args to methods in java. It is being used as a common English word.

You've lost me, boss.

What characters delimit the String: "Here" in the String: "xHerez"
What character is before "Here" and what character is after "Here"?

x and z


x is before and z is after.

Given the String: "xherez"
Now if we change the x to a t and the z to a space we get: "there "
Does that String have the word here in it?

Next change the x to a space and the z to a space we get: " here "
Does that String have the word here in it?

Next change the x to a space and the z to a period we get: " here."
Does that String have the word here in it?

Notice how what values the delimiting characters have determines if there is a word or not. spaces or a period make a word, others do not.

Yes


Yes



Yes


I follow this, at least I think I do, thank you...but I still have no idea how this relates to cat and category.

IF you look at these two sentence:
- This cat is mine
- This catacomb is mine

Why is the cat in second sentence not a profane word? you say it is part of a word?
How can you see that it is part of a word?
Generally speaking, how do you separate one word from each other?

Its a way to find the difference. You want to detect the word cat and not the word category.