Using Text Files

Using Text Files

Students will be able to...

• Read data from external text files using Java’s File and Scanner classes

• Store and analyze file data using arrays and string methods

• Use try-catch blocks to handle IOException errors gracefully

• Parse data using split() and apply algorithms to extract insights

• Read, convert, and analyze numerical data from files

Warm Up

Open Ended

Why might a program need to read information from a file instead of asking the user to type everything

Warm Up

• Handle larger data

• Save time

• Be reused across sessions

Open Ended

What do you expect could go wrong when trying to read a file?

Warm Up

• File might not exist

• Might be in the wrong place

• Might have formatting issues

Try-Catch with IO Exception

• Another way to terminate if an error occurs is to use a try-catch block

  • More graceful

  • Display a more informative message

Try-Catch with IO Exception

• Try Block: write the code to access and manipulate the file data

• Catch Block: explains what to do if a specific error occurs

Try-Catch with IO Exception

• Catch condition: in parentheses, specify the type of error you want to catch

  • Files- IOException error with variable e, which contains info about the exception

Try-Catch with IO Exception

• e.getMessage()- returns a human-readable description of the error

  • Can use in a print statement to inform the user of the error

Now It's Your Turn

• Head to CodeHS and access the Using Text Files modules. You will be completing:

  • Read in a Haiku

  • Karaoke

  • Exploration: Reading Files and Arrays

  • Best Men's Soccer Players: Reading Files and Arrays

  • Exploration: Split Method

Now It's Your Turn!

• Head to CodeHS and access the Using Text Files (Day 2) modules. You will be completing:

  • Exploration: Number of Active Days

  • FitBit: Read in Sleep Data

  • FitBit: Analyze Sleep Data
    

Wrap Up

Match

Match the following concepts:

• Process of reading information from and writing information to files

• Error related to file access or reading

• Java construct to gracefully handle runtime errors

• Method that divides a string based on a delimeter

• Extracting and converting data from Strings

File I/O (File Input/Output)

IOException

try-catch

Split Method

Parsing

• File I/O (File Input/Output)

• IOException

• try-catch

• Split Method

• Parsing

Open Ended

What is the purpose of a try-catch block when working with files?

Wrap Up

• Prevent the program from crashing

• Provide error messages if the file can't be opened
  

Open Ended

How does using an array help when working with data from a file?

Wrap Up

• Stores all entries for later use in one location

  • Helps in filtering, searching, or averaging