---
title: 'Replace w.Write([]byte(fmt.Sprintf())) with fmt.Fprintf() '
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > Datadog Security > Code Security > Static Code Analysis (SAST) > SAST
  Rules > Replace w.Write([]byte(fmt.Sprintf())) with fmt.Fprintf()
---

# Replace w.Write([]byte(fmt.Sprintf())) with fmt.Fprintf()

{% callout %}
# Important note for users on the following Datadog sites: app.ddog-gov.com

{% alert level="danger" %}
This product is not supported for your selected [Datadog site](https://docs.datadoghq.com/getting_started/site.md). ().
{% /alert %}

{% /callout %}

## Metadata{% #metadata %}

**ID:** `go-best-practices/use-fprintf-when-possible`

**Language:** Go

**Severity:** Warning

**Category:** Best Practices

## Description{% #description %}

You do not need to convert the string into a slice of bytes to use `Write`, you can just use the string directly.

## Non-Compliant Code Examples{% #non-compliant-code-examples %}

```go
package main

import (
	"fmt"
	"os"
)

func main(w, a x) {
	r, w := io.Pipe()

	go func() {
		idx, name := "4th", "Mars"

		w.Write([]byte(fmt.Sprintf("The %s planet is %s.\n", idx, name)))
		w.Write([]byte(fmt.Sprint("The ", idx, " planet is ", name, ".\n")))
		w.Write([]byte(fmt.Sprintln("The", idx, "planet is", name, ".")))
		w.Close()
	}()

	if _, err := io.Copy(os.Stdout, r); err != nil {
		log.Fatal(err)
	}
}
```

## Compliant Code Examples{% #compliant-code-examples %}

```go
package main

import (
	"fmt"
	"os"
)

func main() {
	const idx, name = "4th", "Mars"
	n, err := fmt.Fprint(os.Stdout, "The ", idx, " planet is ", name,".\n")
    
	if err != nil {
		fmt.Fprintf(os.Stderr, "Fprint: %v\n", err)
	}
}
```
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