Read a File Line by Line

Documentation

Examples

Process text files line by line and display output in a log widget.

Code

input := widget.NewEntry()
input.Text = "C:/Temp/input.txt"
items := [
    widget.NewFormItem("Path to file", input),
]

output := widget.NewLog(100)
gui.CaptureStdout(func(text) {
    output.Append(text)
})

top := widget.NewForm(items)
border := container.NewBorder(top, nil, nil, nil, output)

data := os.read_file(input.Text)
clean := strings.replace_all(string(data), "\r\n", "\n")

parts := strings.split(clean, "\n")
for i, x := range parts {
    print(string(i) + " " + x)
}

window.SetContent(border)

Key Concepts

File reading: os.read_file() reads entire file
String normalization: Handle both Windows (\r\n) and Unix (\n) line endings
String splitting: strings.split() divides text into lines
Log widget: Display output with scrolling
Capture stdout: Redirect print() statements to log widget

Improvements

Interactive Version

Add a button to reload the file:

btnLoad := widget.NewButton("Load File", func() {
    output.Clear()  // Clear previous content
    data := os.read_file(input.Text)
    clean := strings.replace_all(string(data), "\r\n", "\n")
    parts := strings.split(clean, "\n")
    for i, x := range parts {
        print(string(i) + " " + x)
    }
})

Error Handling

Add error checking:

if !os.exists(input.Text) {
    window.SetStatus("Error: File not found")
    return
}

Use Cases

Log file viewer
Text file processor
Data import tool
File content inspection

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