Best practices in Go - Cheat Sheet & Quick Revision

Recall & Review

beginner

Why should you use clear and descriptive variable names in Go?

Clear and descriptive variable names make your code easier to read and understand, just like using clear labels on boxes helps you find things quickly.

beginner

What is the purpose of using Go's built-in error handling instead of ignoring errors?

Handling errors properly helps your program avoid unexpected crashes and lets you fix problems early, similar to checking if a door is locked before leaving your house.

beginner

Why is it important to keep functions small and focused in Go?

Small, focused functions are easier to understand, test, and reuse, like breaking a big task into simple steps makes it easier to finish.

intermediate

What does 'writing idiomatic Go' mean?

Writing idiomatic Go means using the style and patterns that Go programmers expect, which makes your code easier for others to read and maintain, like speaking the local language when visiting a new place.

intermediate

How does using Go modules improve your project?

Go modules help manage your project's dependencies clearly and reliably, like having a shopping list to keep track of what you need to buy.

What is a good practice when naming variables in Go?

A Use numbers only

B Use random letters

C Use very long names with spaces

D Use short, meaningful names

Short, meaningful names help make code clear and easy to read.

How should errors be handled in Go?

A Check and handle errors explicitly

B Use panic everywhere

C Ignore them

D Print errors and continue without action

Go encourages checking errors explicitly to keep programs safe and predictable.

Why keep functions small in Go?

A To make code harder to read

B To improve readability and testing

C To use more memory

D To confuse other programmers

Small functions are easier to understand, test, and reuse.

What does 'idiomatic Go' mean?

A Using Go in a way that follows common style and patterns

B Writing code in any style you want

C Using only global variables

D Avoiding Go's standard library

Idiomatic Go follows the style and patterns expected by Go programmers.

What is the benefit of using Go modules?

A They remove all errors automatically

B They slow down your program

C They help manage dependencies clearly

D They make your code unreadable

Go modules help keep track of dependencies and versions in your project.

Explain three best practices for writing clean and maintainable Go code.

Think about how to make your code easy to read, safe, and organized.

Describe what 'idiomatic Go' means and why it is important.

Consider how speaking a common language helps communication.

Practice

1. Which of the following is a best practice when naming variables in Go?

easy

A. Use clear and descriptive names that explain the variable's purpose

B. Use single letters for all variable names to save space

C. Use names with special characters to make them unique

D. Use very long names with unnecessary details

Solution

1. Step 1: Understand variable naming importance

   Clear and descriptive names help others understand what the variable holds.

2. Step 2: Evaluate each option

   Using single letters or special characters makes code confusing. Very long names are hard to read.

3. Final Answer:

   Use clear and descriptive names that explain the variable's purpose -> Option A

4. Quick Check:

   Clear names improve readability [OK]

Hint: Pick option promoting clarity and readability [OK]

Common Mistakes:

• Choosing short, unclear variable names
• Using special characters in names
• Making names unnecessarily long

2. Which of the following Go code snippets correctly handles an error returned by a function?

easy

A. result, err := doSomething()
if err = nil {
fmt.Println("Error occurred")
}

B. result, err := doSomething()
if err == nil {
fmt.Println("Error occurred")
}

C. result, err := doSomething()
if err != nil {
fmt.Println("Error occurred")
}

D. result, _ := doSomething()
fmt.Println(result)

Solution

1. Step 1: Identify correct error check syntax

   In Go, errors are checked with 'if err != nil' to detect an error.

2. Step 2: Check each option's error handling

   result, err := doSomething() if err != nil { fmt.Println("Error occurred") } prints an error message when err is not nil, which is correct. result, err := doSomething() if err == nil { fmt.Println("Error occurred") } checks err == nil incorrectly. result, err := doSomething() if err = nil { fmt.Println("Error occurred") } uses assignment '=' instead of comparison '=='. result, _ := doSomething() fmt.Println(result) ignores the error by using _ and prints the result anyway, which is incorrect.

3. Final Answer:

   result, err := doSomething() if err != nil { fmt.Println("Error occurred") } -> Option C

4. Quick Check:

   Check error with 'err != nil' [OK]

Hint: Remember: error check is 'if err != nil' [OK]

Common Mistakes:

• Using '=' instead of '==' in conditions
• Checking 'err == nil' to detect errors
• Ignoring errors without handling

3. What will be the output of the following Go code?

package main
import "fmt"
func main() {
    nums := []int{1, 2, 3}
    sum := 0
    for _, n := range nums {
        sum += n
    }
    fmt.Println(sum)
}

medium

A. 6

B. 123

C. 0

D. Error

Solution

1. Step 1: Understand the loop and sum calculation

   The loop goes through each number in nums: 1, 2, 3 and adds them to sum.

2. Step 2: Calculate the sum

   sum = 0 + 1 + 2 + 3 = 6

3. Final Answer:

   6 -> Option A

4. Quick Check:

   Sum of [1,2,3] = 6 [OK]

Hint: Sum elements by adding each in the loop [OK]

Common Mistakes:

• Concatenating numbers as strings
• Starting sum from wrong initial value
• Misunderstanding range loop syntax

4. Identify the error in the following Go code snippet and choose the best fix:

func divide(a, b int) int {
    return a / b
}

func main() {
    result := divide(10, 0)
    fmt.Println(result)
}

medium

A. Change function to return float64 instead of int

B. Add error handling to check if b is zero before dividing

C. Remove the divide function and do division inline

D. Ignore the error since Go handles division by zero automatically

Solution

1. Step 1: Identify the problem with division by zero

   Dividing by zero causes a runtime panic in Go, which must be prevented.

2. Step 2: Choose the fix that prevents panic

   Adding error handling to check if b is zero before dividing avoids the panic. Changing return type or removing function does not fix the error. Go does not handle division by zero automatically.

3. Final Answer:

   Add error handling to check if b is zero before dividing -> Option B

4. Quick Check:

   Prevent division by zero [OK]

Hint: Always check divisor before dividing to avoid panic [OK]

Common Mistakes:

• Ignoring division by zero errors
• Assuming Go handles zero division safely
• Changing return type without fixing logic

5. You want to write a Go function that returns a map of words to their counts from a slice of strings. Which approach follows best practices for clarity, error handling, and simplicity?

hard

A. Use nested loops to count words multiple times for accuracy

B. Use global variables to store counts and update them inside the function

C. Return a pointer to the map and panic if input slice is empty

D. Use a simple loop to count words, return the map, and handle empty input gracefully

Solution

1. Step 1: Understand best practices for function design

   Functions should be simple, clear, and handle edge cases like empty input without panicking.

2. Step 2: Evaluate each option

   Use a simple loop to count words, return the map, and handle empty input gracefully uses a simple loop and handles empty input gracefully, which is best practice. Use nested loops to count words multiple times for accuracy is inefficient with nested loops. Return a pointer to the map and panic if input slice is empty uses panic and pointers unnecessarily. Use global variables to store counts and update them inside the function uses global variables, which reduces clarity and safety.

3. Final Answer:

   Use a simple loop to count words, return the map, and handle empty input gracefully -> Option D

4. Quick Check:

   Simple, clear, safe function [OK]

Hint: Keep functions simple and handle edge cases safely [OK]

Common Mistakes:

• Using complex nested loops unnecessarily
• Panicking instead of returning errors
• Using global variables inside functions