Explain the use of Go's range keyword for iterating over collections?

Table of Contents

• Introduction
• Using Go's range Keyword for Iterating Over Collections
  • Iterating Over Arrays and Slices
  • Iterating Over Maps
  • Iterating Over Strings
  • Iterating Over Channels
• Practical Examples Using range
  • Example : Filtering Values from a Slice
  • Example : Counting Characters in a String
• Conclusion

Introduction

In Go, the range keyword is a powerful tool used to iterate over various types of collections such as arrays, slices, maps, strings, and channels. It provides a concise and readable way to loop through elements in these data structures. Understanding how to effectively use the range keyword can make your code more efficient and easier to understand.

Using Go's range Keyword for Iterating Over Collections

Iterating Over Arrays and Slices

The range keyword allows you to iterate over each element of an array or slice. When iterating over an array or slice, range returns two values: the index and the element at that index.

• Example: Iterating Over an Array or Slice

  Outpu

  In this example:

  • For the array arr, range returns the index (0 to 4) and the corresponding value.
  • For the slice slice, range works similarly, iterating over each element.

Iterating Over Maps

When using range to iterate over a map, it returns two values: the key and the value associated with that key. This allows you to easily access all key-value pairs in the map.

• Example: Iterating Over a Ma

  Output

  Here, range iterates over each key-value pair in the map person, printing the key and its corresponding value.

Iterating Over Strings

Using range with strings allows you to iterate over Unicode code points (runes) in the string. The range expression returns the index of the character and its rune value.

• Example: Iterating Over a String

  Output:

  In this example, range correctly handles Unicode characters in the string "Hello, 世界," providing the index and the rune value of each character.

Iterating Over Channels

range can also be used to receive values from a channel until it is closed. When iterating over a channel with range, it retrieves each value sent on the channel and stops when the channel is closed.

• Example: Iterating Over a Channel

  Output:

  Here, range continues to receive values from the channel ch until the channel is closed by the sender.

Practical Examples Using range

Example : Filtering Values from a Slice

You can use range to filter specific values from a slice based on a condition.

Output:

In this example, range is used to loop through each number in the slice numbers and filter out even numbers.

Example : Counting Characters in a String

You can use range to count the occurrences of each character in a string.

Output:

In this example, range iterates over each character in the string text and counts their occurrences using a map.

Conclusion

The range keyword in Go is a versatile tool for iterating over collections like arrays, slices, maps, strings, and channels. It provides a concise and readable way to access elements and perform operations on them. By leveraging the range keyword effectively, you can write more efficient and maintainable Go code. Whether you need to iterate over an array, process map keys, handle Unicode strings, or work with channels, range offers a simple solution for iteration in Go.