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Understanding Strings

Course video 24 of 66

This module begins with a short presentation from Raluca Gordân, an assistant professor in Duke University’s Center for Genomic and Computational Biology, about an important problem genomics scientists encounter regularly: how to identify genes in a strand of DNA. To tackle this problem, you will need to understand strings: series of characters such as letters, digits, punctuation, etc. After learning about Java methods that work with strings, you will be able to find genes within a DNA string as well as tackle other string related problems, such as finding all of the links in a web page. By the end of this module, you will be able to: (1) Use important methods for the Java String class; (2) Use conditionals, for loops, and while loops appropriately in a Java program; (3) Find patterns in the data represented by strings to help develop the algorithm for your program; (4) Understand the importance of designing programs that keep different data processing steps separate; (5) Use the StorageResource iterable for this course to store some data for further processing; and (6) Rely on Java documentation to better understand how to use different Java packages and classes.

Java Programming: Solving Problems with Software

Duke University

Kurs 1 von 4 in Object Oriented Programming in Java Spezialisierung

Learn to code in Java and improve your programming and problem-solving skills. You will learn to design algorithms as well as develop and debug programs. Using custom open-source classes, you will write programs that access and transform images, websites, and other types of data. At the end of the course you will build a program that determines the popularity of different baby names in the US over time by analyzing comma separated value (CSV) files. After completing this course you will be able to: 1. Edit, compile, and run a Java program; 2. Use conditionals and loops in a Java program; 3. Use Java API documentation in writing programs. 4. Debug a Java program using the scientific method; 5. Write a Java method to solve a specific problem; 6. Develop a set of test cases as part of developing a program; 7. Create a class with multiple methods that work together to solve a problem; and 8. Use divide-and-conquer design techniques for a program that uses multiple methods.

Lehrplan anzeigen

Skills You'll Learn

Algorithms, Problem Solving, String (Computer Science), Java Programming

Unterrichtet von

Owen Astrachan
Professor of the Practice
Robert Duvall
Lecturer
Andrew D. Hilton
Associate Professor of the Practice
Susan H. Rodger
Professor of the Practice

Skript

Hi, and welcome to this lesson on finding information and patterns in data.

Which is a very general topic that we will make concrete,

in working with Java strings.

Strings are sequences of letters, digits,

punctuation, any character that you might type for example.

Why will you learn about strings?

You've learned previously that everything is a number.

That's true as you can see here,

where I've captured the beginning of three different files.

These files might be stored in memory,

on a flash drive,

or on your computer's hard drive.

The first file, was a video.

A file with a.mp4 suffix.

The second file was an image,

a file with a.png suffix.

The third file was a plain text file with a.txt suffix.

Can you tell which group of bits of zeros and ones goes with which file,

by simply looking at the zeros and ones?

Some people may be able to do that, but most cannot.

Although everything stored on a computer as a number,

information stored on a computer is often readable.

We use strings to sort data,

so that we can read it,

and so that we can write programs to read the data and process it.

Here are parts of three data files,

where the data are stored as strings.

It's important that the data is readable by you,

not just by the computer.

Although we could write programs even if everything was only a number,

it will be easier to write programs to find patterns,

knowledge and information and data,

when the data is stored as strings.

The first part of a file is genomic data,

stored in what's called fasta format.

You write programs in this lesson to find proteins,

and genes, and genomic data.

The second part of a file is from a web-page.

You will write programs to find links and other information in a web-page.

Doing at a small scale what search engines like Google do,

in ranking pages to be found by those doing web searches.

The third part of a file is data from a CSV file,

or Crime in Sacramento California in 2008.

The CSV file, is a file in a special format.

The CSV means, Comma Separated Values.

You will write code in a later lesson to process CSV files.

We have several goals for you to learn, as part of this lesson.

You'll learn about the Java string class.

You'll learn many details how to write programs with the string class,

and how that's most often done.

You'll learn common string functions,

and how to read documentation to find out more about strings.

You'll learn about Java types and operators.

Here you'll learn more about Java's numeric types and operators, on those types.

Which for you will be int or integer,

and double or a floating point number.

You'll learn about programming to find patterns in data,

by searching for specific parts of a string.

You'll repeat searches to find information and patterns,

like all the links on a web page,

or all the genes in a strand of DNA.

Let's get started solving problems. Thank you.

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