Write a Java program to check whether a string contains only a certain set of characters (in this case a-z, A-Z and 0-9).

JAVA Advanced System Development.

1. Write a regular expression that will match a string that starts with a series of letters. The letters must be followed by a period. After the period, there must be a series of digits. The string “kjisl.22” would match. The string “f4.12b” would not. Use the following string to test your regular expression:

 

String problem1 = “abcd.135”;

 

1. Modify the regular expression in problem 1 to use a group, so that we can print all the digits that occur in a string that contains multiple occurrences of the pattern. Write all the code required to accomplish this (create a pattern and matcher etc.). Use the following string to test your code:

 

String problem2 = “abcd.135uvqz.7tzik.888”;

 

There are three occurrences of the pattern we looked for in problem 2. When you run your code, you should see 135, 7, and 888 printed to the console.

 

1. Let’s suppose we are reading strings that match the patterns we used in problem 1 and 2 from a file. Tabs are used to separate the matches, with one exception. The last match is followed by a newline. Our revised problem 2 string would look like this:

 

String problem3 = “abcd.135\tuvqz.7\ttzik.888\n”;

 

Revise the regular expression accordingly and extract all the numbers, as you did in problem 2.

 

1. Instead of printing out the numbers themselves, print out their start and end indices. Use the same string you used for problem 3. Make those indices inclusive. For example, the start index printed for 135 should be 5, and the end index should be 7. Hint: You will need to look at the documentation for the

Matcher.start() and Matcher.end() methods. There is more than one version of these methods. The documentation is here:

https://docs.oracle.com/javase/8/docs/api/java/util/regex/Matcher.html

 

1. Suppose we have the following string containing points on a graph within curly braces. Extract what is in the curly braces.

 

String problem4 = “{0, 2}, {0, 7}, {1, 3}, {2, 4}”;

 

 

1. Write a Java program to remove the specific letters from a string and return the new string. Specific letters: “p”, “q”, or “r”.

If the given string does not contain “p”, “q”, or “r”, return “Not found.”

1. Write a Java program to check whether a string contains only a certain set of characters (in this case a-z, A-Z and 0-9).

 

You should name your project Practice. Put your solutions to all the above problems in the Main.java file.