When building a website, we often need to handle various data, not just simply display them.For example, we may need to calculate the total price of goods, the remaining inventory, or dynamically adjust the style of elements based on numerical values.These scenarios naturally lead to a core issue: Does the Anqi CMS support direct arithmetic operations on strings or numbers in templates, thereby flexibly affecting the display of content?

The answer is affirmative.The template engine of Anqi CMS cleverly inherits many advantages of Django templates, including direct support for arithmetic operations.This means you can use various operators and filters in the frontend template files to perform operations such as addition, subtraction, multiplication, division, modulo, and control the display of content based on the result of the calculation.

Direct Arithmetic Operations:calcFlexible Use of Tags

AnQi CMS providescalcTags allow users to directly write arithmetic expressions in templates, their syntax is very intuitive, similar to the mathematical expressions we use in daily life.Whether it is an integer, a floating-point number, or various complex combinations, all can be completed within this tag.

For example, if you want to display the subtraction result of two numbers on the page, you can write it like this:{{ 10 - 100 }}

You need to calculate the product of the unit price of the goods and the quantity, taking into account the floating-point number:{{ item.Price * item.Quantity }}

Or, in a loop, determine if a number is a multiple of a certain value and perform a modulus operation:{{ (loop.index + 7) % 7 }}

These expressions not only support basic addition:+), subtraction (-), multiplication (*), division (/), but also support power operations:^）and modulus operation（%），even handling logical expressions such astrue || false（or）andtrue && false(And), making the template's logical judgment more rich. In this way, you can easily realize functions such as automatically calculating the discount price when the inventory quantity reaches a certain threshold.

Using filters to achieve more refined numerical processing

In addition to direct arithmetic operation tags, Anqi CMS also provides a large number of practical filters, which can format, trim, or perform specific calculations on data, greatly enhancing the expressiveness of templates.

  • addFilter:Specifically used for the addition of numbers or strings.It is very intelligent and can automatically try to convert types for addition operations, even if it is a mix of strings and numbers, it can give a result within a reasonable range.{{ item.BasePrice|add:item.ShippingCost }}

  • integerandfloatFilter:It is crucial to ensure the correct data type before performing arithmetic operations. If the 'number' obtained from the background is actually a string type, for example, the article page views"12345"you can useintegerorfloatThe filter converts it to a true numeric type for subsequent calculations:{% set views = article.Views|integer %} {% set price = product.Price|float %}

  • floatformatFilter:When dealing with monetary amounts or statistics, we often need to control the number of decimal places.floatformatThe filter allows you to precisely specify the number of decimal places to retain in floating-point numbers, even to set it to round off or not to display extra zeros:{{ product.Price|floatformat:2 }}(Retain two decimal places){{ totalAmount|floatformat }}(Default behavior, adjust as needed)

  • stringformatFilter:If you need more flexible formatting, such as embedding the calculation result into a specific text, or outputting according to the Go language's formatting string rules,stringformatthe filter is very useful:{{ 888|stringformat:"库存: %d 件" }}

  • Other number-related filters:There are some filters for specific scenarios, such asdivisiblebyCan determine whether one number can be evenly divided by another,get_digitCan obtain the number at a specified position in the number, and these can all be assisted to complete more complex number logic display in the template.

Combination of variable assignment and logical control

To implement more complex calculation logic, or to use intermediate results for subsequent operations, the variable assignment feature in the template is particularly important. Anqi CMS'ssetandwithThe tag allows you to declare and assign variables in the template, making step-by-step operations possible:

{% set subtotal = item.Price * item.Quantity %} {% set total = subtotal|add:shippingCost %} <div>总计：{{ total }} 元</div>

These calculation results are often associated with conditional judgments (if标签) 结合使用，比如根据商品总价的不同显示不同的优惠信息，或者根据库存数量决定是否显示“缺货”提示。在循环展示列表数据时，我们经常需要用到循环计数器（ English) Combine them, for example, to display different discount information based on the different total prices of goods, or to decide whether to display "Out of Stock" prompts based on the inventory quantity. When displaying a list of data in a loop, we often need to use a loop counter (forloop.Counterandforloop.Revcounter），They are numbers themselves and can be directly involved in calculations, such as applying different styles every N items or calculating the percentage of completion.

Summary

The AutoCMS provides powerful and flexible arithmetic operation capabilities in templates, making it easier to dynamically display website content.Through direct arithmetic expressions, rich filters, and variable assignment functions, you can transform the original data obtained from the backend into information that meets the needs of front-end display, with more interactivity and visual appeal.This not only improves the expressiveness of the content, but also gives website operators greater flexibility, without the need to modify the backend code to achieve many dynamic effects.

Common Questions (FAQ)

1. Can the arithmetic operations in the Anqi CMS template handle very complex business logic?The arithmetic operations in the Anqi CMS template mainly focus on datapresentation levelThe calculation and formatting.For complex logic involving database transactions, multi-step complex business rule judgments, or sensitive data processing, it is usually recommended to complete it on the backend (controller or service layer) and then pass the calculated final result to the template for display.This ensures the system's security and performance, while maintaining a clear separation of front-end and back-end responsibilities.

2. Can multiple arithmetic operations be combined in an expression?Yes, you can combine multiple arithmetic operations in an expression, such as addition, subtraction, multiplication, division, and modulus. The template engine will process it according to the standard mathematical operation precedence.{{ (item.Price * item.Quantity) - item.Discount }}First, multiplication will be calculated, then subtraction will be performed. To ensure the operation order meets expectations, it is recommended to use parentheses.()To clarify grouping.

3. What happens if the data involved in the operation is not a numeric type?If the data involved in the operation is not a numeric type and has not passedintegerorfloatThe filter performs an explicit conversion, and the template engine of the Safe CMS may ignore non-numeric parts or return default values (such as 0) instead of producing an error that causes the page to crash. To avoid potential problems, it is recommended to always useintegerorfloatThe filter ensures that the variable is of the expected numeric type.