Strings Tutorial, Simple Filtering

Strings Tutorial

Simple Filtering

Complex Filters

Pattern Matching

String Functions

Contains

Ends With

Equal Strings

Find Position

Formatting

Using Print Formatting

Lower Case

Join Strings

Starts With

String Length

Special Characters

Split a String

Substring

Upper Case

These questions use the simple text file http://progzoo.net/greeks.txt - this file includes around three hundred characters from Greek legends.

You will need to use string methods such as: length equal substring contains indexOf

Io

Io was a beautiful maiden who had an unfortunate run-in with Zeus and Hera. Io was turned into a heifer plagued by a gadfly.

Print the only two character name.

Hint

Test the length() method

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import java.io.BufferedReader; import java.io.FileReader; public class Greek { public static void main(String[] argv) throws Exception { BufferedReader fh = new BufferedReader(new FileReader("greeks.txt")); String greek; while ((greek=fh.readLine())!=null) { if (greek.length()==4) { System.out.println(greek); } } } }

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test text

 

 

 

 

seus

Odysseus, Perseus and and the other guy all traveled widely and slew monsters.

Identify the three characters where the name ends with "seus".

Hint

Use the greek.endsWith("seus") as your condition.

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import java.io.BufferedReader; import java.io.FileReader; public class Greek { public static void main(String[] argv) throws Exception { BufferedReader fh = new BufferedReader(new FileReader("greeks.txt")); String greek; while ((greek=fh.readLine())!=null) { System.out.println(greek); } } }

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test text

 

 

 

 

Cassandra

Cassandra was cursed with the gift of prophecy. She has a nine letter name that ends with "a". Find the others.

Print the names with 9 letter that end in "a".

Hint

You can use the and operator && to test that two conditions are both true.

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import java.io.BufferedReader; import java.io.FileReader; public class Greek { public static void main(String[] argv) throws Exception { BufferedReader fh = new BufferedReader(new FileReader("greeks.txt")); String greek; while ((greek=fh.readLine())!=null) { if (greek.startsWith("C") && greek.endsWith("a")) System.out.println(greek); } } }

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test text

 

 

 

 

Amazons

The Amazons were a fearsome race of warrior women. Their name has an "m" as the second character.

Print the names with "m" as the second character.

Hint

greek.substring(1,2) will give the second character of the string.

Hint

Don't forget that we must use greek.substring(1,2).equals("m") rather than greek.substring(1,2)=="m"

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import java.io.BufferedReader; import java.io.FileReader; public class Greek { public static void main(String[] argv) throws Exception { BufferedReader fh = new BufferedReader(new FileReader("greeks.txt")); String greek; while ((greek=fh.readLine())!=null) { System.out.println(greek); } } }

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test text

 

 

 

 

Ixion

Ixion murdered his father-in-law and got on the wrong side of Zeus - two mistakes.

The name Ixion includes an "x", but it does not end in "x" so he is included in our list. The "x" in Ajax is at the end - so he is excluded.

Print the names with an "x", where the name does not end with x.

Hint

We could use contains("x") and endsWith("x") - remember that we can use these in combination with:

&&         ||        !

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import java.io.BufferedReader; import java.io.FileReader; public class Greek { public static void main(String[] argv) throws Exception { BufferedReader fh = new BufferedReader(new FileReader("greeks.txt")); String greek; while ((greek=fh.readLine())!=null) { System.out.println(greek); } } }

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test text

 

 

 

 

Terminal o

Several folk have a name ending in "o". We only want them if that is the only "o" in their name.

The sun god Apollo represents order, harmony and civilization; but he does not make our list as he has an "o" before the end of his name.

Print where the first "o" is the last character.

Hint

The expression greek.indexOf("o") should be the length of the string minus 1.

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import java.io.BufferedReader; import java.io.FileReader; public class Greek { public static void main(String[] argv) throws Exception { BufferedReader fh = new BufferedReader(new FileReader("greeks.txt")); String greek; while ((greek=fh.readLine())!=null) { System.out.println(greek); } } }

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test text