In our security CMS, we often need to handle various data and present it flexibly to visitors.Whether it is a simple number calculation or complex text concatenation, I hope it can be completed with a simple and intuitive method.addIt shows excellent flexibility in handling variable addition, which can help us build dynamic content more efficiently and intelligently.

addFilter: 'Art of Addition' in the template

addFilter is a powerful tool provided by the AnQi CMS template engine, its core function is to implement the 'addition' operation of variables.Here, 'addition' is not limited to the mathematical sense of summation, it can also cleverly handle string concatenation, and even perform intelligent conversions between different types of variables to achieve the desired result.

The easy summation of numbers

Imagine, we need to display a dynamic total on the page, such as the number of items in the shopping cart, the number of people registered for an event, or the cumulative page views. When both variables contain numbers,addThe filter will perform standard mathematical addition as expected. Whether it is an integer or a floating-point number, it can calculate accurately, making your data presentation clear at a glance.

For example, if you have two variables representing quantities, you can add them directly like this:{{ 5|add:2 }}it will output7. If you need to handle larger numbers, such as:{{ 5|add:40 }}Then you will get47.

This intuitive ability to add numbers makes data statistics and display in templates extremely convenient.

Seamless concatenation of strings

In content operation, it is common to combine different text fragments into a complete sentence, title, or phrase.addThe filter operates just as smoothly here. When both operands are strings, it performs string concatenation, connecting the two into a new string.

For example, you want to display the system name and module name combined:{{ "安企"|add:"CMS" }}It can be easily concatenated.安企CMSThis feature is very useful when building dynamic navigation, generating personalized messages, or combining article summaries.

Where does the flexibility of adding across types manifest?

addThe true highlight of the filter lies in its intelligent conversion ability when handling different types of variables. In many cases, we may encounter scenarios where we need to combine numbers with strings.addThe filter attempts to perform type conversion to complete the operation, which greatly simplifies our template code.

For example, if you try to add a number with a string,addThe filter will typically convert numbers to strings first and then concatenate them.{{ 5|add:"CMS" }}You will get5CMS.{{ "安企"|add:"2" }}it will output安企2.

This intelligent conversion is especially convenient for generating dynamic numbers, constructing descriptions with specific IDs, or creating text containing numerical information, which saves the麻烦的手动类型转换步骤.

However, this intelligent conversion is not omnipotent. IfaddThe filter cannot successfully convert a variable into a type that can be added or concatenated (for example, trying to add a number with a completely unrelated, unparseable text string, or with anil/空值相加），它会选择Englishignore那个无法处理的部分，只返回有效部分的原始值。English

比如，如果您有一个未定义的变量EnglishnothingIt typically represents a null value in the Anq CMS template), try adding it to a number:{{ 5|add:nothing }}The output will be5, because it recognizes thatnothingUnable to participate in valid numerical or string operations, therefore it was ignored.

Overview of actual application scenarios

addThe flexibility of the filter is widely used in the daily operation and template design of the security CMS:

  1. Dynamic messages and prompts:Combine user ID or article ID to generate personalized welcome messages, notifications, or download links. For example,{{ "欢迎用户"|add:userId|add:"下载最新报告" }}.
  2. Content data summary:On the list page or detail page, quickly calculate and display the sum of certain values, such as the number of comments, likes, etc.
  3. URL parameter construction:When generating links with dynamic parameters, you can concatenate the base URL with ID or other string parameters.
  4. Product number or SKU generation:Automatically generate product codes with certain rules for convenient management and display.

Use suggestions and precautions

AlthoughaddThe filter provides great convenience, but in actual use, we still recommend that you maintain a clear understanding of variable types and use them reasonably according to the expected results.Especially when dealing with mixed type variables, understanding its automatic conversion and ignoring mechanism can help you avoid potential display errors and ensure that the content is presented accurately according to your expectations.When you need to perform more complex mathematical operations (such as subtraction, multiplication, division), the Anqi CMS template also provides special arithmetic operation tags to meet these needs.

Common Questions (FAQ)

  1. addWhat is the priority of type conversion when a filter performs addition of numbers and strings mixed together?In most cases,addThe filter will attempt to convert numbers to strings when adding numbers and strings together, and then perform string concatenation. For example,{{ 10|add:"件商品" }}You will get"10件商品".

  2. IfaddOne of the operands of the filter is a null value (such asnilOr an undefined variable), what will happen?WhenaddOne operand of the filter is null,nilor when it is an unparseable type,ignoreThis operation is invalid, it only returns the original value of another valid operand. For example,{{ 100|add:unDefinedVar }}It will still be output100.

  3. addDoes the filter support subtraction, multiplication, and other mathematical operations? addThe filter is mainly used for addition and string concatenation. For other arithmetic operations such as subtraction, multiplication, and division, the Anqi CMS template provides special算术运算标签 (English)(such ascalcTags) to handle, you can refer to the relevant documentation for more detailed usage instructions.