How to Access Elements from Parallel Arrays Using Index Within Range in HTML/Template?

How to Iterate Through Parallel Arrays Using Index within Range in HTML/Template

In HTML/Template, utilizing the range construct along with the index function allows for iterating through multiple arrays in parallel. However, a common pitfall occurs when attempting to access elements from an array using the index within the range block.

Consider the following code:

{{range $i, $e := .First}}{{$e}} - {{index .Second $i}}{{end}}

This code attempts to iterate through the arrays .First and .Second in parallel. However, it fails to work correctly because the dot (.) variable within the range block has been reassigned to the value of .First. To resolve this issue, we need to access the original dot variable, which represents the entire data set.

The index function takes the first argument as the array to be indexed and subsequent arguments as the index values. Therefore, we can modify the code as follows:

{{range $i, $e := .First}}{{$e}} - {{index $.Second $i}}{{end}}

Here, $ represents the original dot variable, which contains the data argument passed to Execute. By using $, we can access the elements of .Second using the index $i.

Alternatively, a cleaner approach is to create a template function called zip that accepts multiple slices and returns a slice of each pair of values. This eliminates the need for complex indexing within the template and enhances code readability.

The above is the detailed content of How to Access Elements from Parallel Arrays Using Index Within Range in HTML/Template?. For more information, please follow other related articles on the PHP Chinese website!