File.write for writing in Ruby - Step-by-Step Execution

Concept Flow - File.write for writing

Start

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Call File.write with filename and content

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Open file in write mode

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Write content to file

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Close file

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Return number of bytes written

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End

The program calls File.write with a filename and content, opens the file, writes the content, closes the file, and returns the number of bytes written.

Execution Sample

Ruby

bytes = File.write("hello.txt", "Hello, Ruby!")
puts bytes

Writes 'Hello, Ruby!' to 'hello.txt' and prints the number of bytes written.

Execution Table

Step	Action	Evaluation	Result
1	Call File.write with filename 'hello.txt' and content 'Hello, Ruby!'	File.write("hello.txt", "Hello, Ruby!")	Opens 'hello.txt' for writing
2	Write content 'Hello, Ruby!' to file	Write string to file	File contains 'Hello, Ruby!'
3	Close file	File closed	File saved with content
4	Return number of bytes written	Length of 'Hello, Ruby!'	13
5	Assign return value to variable bytes	bytes = 13	bytes = 13
6	Print bytes	puts bytes	13 printed to console

💡 File.write completes after writing content and returns byte count

Variable Tracker

Variable	Start	After File.write	Final
bytes	nil	13	13

Key Moments - 3 Insights

Why does File.write return a number?

File.write returns the number of bytes written to the file, as shown in execution_table step 4, so you know how much data was saved.

Does File.write create the file if it doesn't exist?

Yes, File.write opens the file in write mode and creates it if missing, as seen in execution_table step 1.

What happens if the file already has content?

File.write overwrites existing content, replacing it with the new string, as shown in step 2.

Visual Quiz - 3 Questions

Look at the execution_table, what is the value of 'bytes' after File.write completes?

A 13

B 11

C nil

D 0

💡 Hint

Check execution_table row 4 and variable_tracker for 'bytes' value after writing.

At which step does the file get closed?

A Step 4

B Step 2

C Step 3

D Step 1

💡 Hint

Look at execution_table step 3 for file closing action.

If the string written was empty, what would File.write return?

A nil

B 0

C 1

D Error

💡 Hint

File.write returns the number of bytes written, so empty string means zero bytes (see step 4).

Concept Snapshot

File.write(filename, content) opens or creates a file named filename,
writes the content string to it, overwriting existing data,
closes the file, and returns the number of bytes written.
Use it to quickly save text to a file in Ruby.

Full Transcript

This example shows how File.write works in Ruby. When you call File.write with a filename and some text, Ruby opens the file for writing. If the file doesn't exist, it creates it. Then it writes the text into the file, replacing any old content. After writing, it closes the file to save changes. Finally, it returns the number of bytes written, which you can store in a variable. In the example, 'Hello, Ruby!' is written to 'hello.txt', and the program prints 13, the number of bytes written. This helps you confirm the write was successful.