7. Files and Text#
Most useful programs eventually read data from outside the program or write results somewhere durable. This chapter introduces file operations and text processing so you can work with multi-line content and structured records.
File I/O: File input and output let a program read stored data and save results.
Streams: Streams provide a sequence-oriented way to read from or write to a source.
Text processing: Trimming, casing, splitting, and replacing help clean and transform text.
Structured records: Delimited text such as CSV stores fields that must be parsed and validated.
Regular expressions: Regex patterns describe text shapes for search, validation, and extraction.
Reliable text handling turns raw files, exports, logs, and user-entered records into data a program can actually use.
Video
Read and Write files in 10 minutes | C# by tutorialsEU.
This video remains hosted on YouTube and is the property of its original creator or rightsholder; it is embedded here via YouTube’s official player for educational reference only.
Learning Objectives
By the end of this chapter, you will be able to:
Read text from files and write text output safely
Clean text with trimming, casing, splitting, and replacement methods
Parse structured text lines into typed values
Validate fields before using parsed data
Use regular expressions for targeted text search and matching