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44 lines
1.6 KiB
Markdown
44 lines
1.6 KiB
Markdown
# Arrays
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## What is an Array?
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- Object used to store a **list** of values
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- All values in array are the **same type**
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-Eg. int, double, char, string, etc
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- Used to store a large number of data
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- Easy to **access** any element in the array
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## How to Declare
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- Declaring an array to up to 10 words
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```java
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String array[] = new String[10];
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```
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- Declaring an array and initializing variables at the same time:
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```java
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String array[] = {"s", "d", "f"};
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```
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## String Manipulataion
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- ```length()` to find the length of a string
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- `stringName.charAt(0)` will output the first character
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- Each character in a string has a positio. String positions start at 0
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- `stringName.indexOf("T")` will output the index number that the letter `T` belongs to
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- `stringName.substring(3)` will output all characters after the index #
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- Eg. `string stringName = "Jim hates math"`
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- Output: `hates math`
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- First # is for the index that you want and last number is for the index that you don't wnat
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- `stringName2 = " i hate math "`
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- `stringName2.trim();
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- output: i hate math"`
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- `stringName.toLowerCase()` makes every character a lower case letter
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- `stringName.toUpperCase()` makes every character an upper case letter
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- concat()
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- `stringname1.concat(stringname2);` will put both string into 1 word
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- `stringname.replce("a", "p");` will replace every `'a'` with `'p'`
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- `stringname1.equals(stringname2);` will return true of false depending on whether the two contain the same value
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- `stringname1.compareTo(stringname2);` is for alphabetical order
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- if the condition above is < 0, name1 is before name2. >0, name1 is before name2, if =0, its the same string
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