In AnQiCMS template development, we often encounter situations where we need to handle various types of data.Sometimes, data obtained from a database or entered by a user, even if they represent numbers, may be treated as string type by the system in the template layer.In this case, if mathematical operations or numerical comparisons are performed directly on these 'number strings', unexpected results or even errors may occur.Therefore, understanding how to convert numeric strings to integer or floating-point number types in AnQiCMS templates is crucial for ensuring the accuracy of data processing and the correctness of logic.

AnQiCMS's template engine provides a rich set of filters (Filter), which can help us easily transform and process data. We mainly use these filters for converting numeric strings into specific numeric types,integerandfloatThese two filters.

Understanding the necessity of type conversion

Imagine a scenario where you need to sort by the "reading quantity" of an article or calculate the "total price" by multiplying the "unit price" by "quantity". If the fields such as "reading quantity

  • "100" + "50"可能得到"10050"Instead150.
  • "5" > "10"可能会评估为True，因为字符串比较是逐个字符进行的（’5’ 大于 ‘1’），而不是数值比较。

By explicitly converting these strings to integers or floating-point numbers, we can ensure that the correct mathematical operations and logical judgments are performed.

Convert string to integer:integerFilter

When you need to convert a numeric string to an integer, you can useintegera filter. This filter will try to parse the input value and return its corresponding integer form.

Use syntax:

{{ 您的变量 | integer }}

Example demonstration:

Suppose you have a variableitem.CountIt may be a numeric string, and you want to use it as an integer:

{% set stringNumber = "123" %}
{% set stringFloat = "5.8" %}
{% set stringText = "hello" %}

<p>字符串 "123" 转换为整数: {{ stringNumber | integer }}</p>
<p>字符串 "5.8" 转换为整数: {{ stringFloat | integer }}</p>
<p>字符串 "hello" 转换为整数: {{ stringText | integer }}</p>
<p>直接数字 456 转换为整数: {{ 456 | integer }}</p>

Expected output:

<p>字符串 "123" 转换为整数: 123</p>
<p>字符串 "5.8" 转换为整数: 5</p>
<p>字符串 "hello" 转换为整数: 0</p>
<p>直接数字 456 转换为整数: 456</p>

As can be seen from the example,integerThe filter automatically truncates the decimal part during float conversion. If the input string cannot be parsed as a valid number (e.g., "hello"), it will return0.

Convert a string to a floating-point number:floatFilter

When you need to convert a numeric string to a floating-point number (i.e., a number with a decimal point), you can usefloatFilter. This filter attempts to parse the input value and return it in its corresponding floating-point form.

Use syntax:

{{ 您的变量 | float }}

Example demonstration:

Suppose you have a variableitem.PriceIt may be a numeric string that you want to calculate as a floating-point number:

{% set stringNumber = "123" %}
{% set stringFloat = "5.8" %}
{% set stringText = "hello" %}

<p>字符串 "123" 转换为浮点数: {{ stringNumber | float }}</p>
<p>字符串 "5.8" 转换为浮点数: {{ stringFloat | float }}</p>
<p>字符串 "hello" 转换为浮点数: {{ stringText | float }}</p>
<p>直接数字 456 转换为浮点数: {{ 456 | float }}</p>

Expected output:

<p>字符串 "123" 转换为浮点数: 123.000000</p>
<p>字符串 "5.8" 转换为浮点数: 5.800000</p>
<p>字符串 "hello" 转换为浮点数: 0.000000</p>
<p>直接数字 456 转换为浮点数: 456.000000</p>

WithintegerFilter similar, if the input string cannot be parsed as a valid number,floatthe filter will return0.000000.

Use in combination with注意事项

In practical development, you may need to use these two filters together, for example, convert them to floating-point numbers first and then to integers to ensure they are truncated down, or perform more complex numerical processing.

For example, calculate the total price of goods:

{% set productPrice = "99.50" %} {# 可能是字符串 #}
{% set productQuantity = "3" %}  {# 可能是字符串 #}

{% set priceFloat = productPrice | float %}
{% set quantityInt = productQuantity | integer %}

<p>商品单价: {{ priceFloat }}</p>
<p>购买数量: {{ quantityInt }}</p>
<p>总价: {{ priceFloat * quantityInt }}</p>

Important reminder:

  • Data validation:When performing type conversion, always be aware of the data source. If the input string is not a valid number format,integerit will return0,floatit will return0.0。In critical business logic, you may need additional conditional judgments to handle these 'invalid'0values to avoid incorrect calculations.
  • Chain operations:Filters can be chained, for example{{ "5.6" | float | integer }}Will be converted first5.6Then converted5.
  • Go Language date format:Although not directly related to numeric conversion, the AnQiCMS backend is developed based on Go language, and the timestamp formatting functions in the template (such asstampToDate）Follow the time formatting rules of the Go language, for example2006-01-02 15:04:05. Familiarity with these rules helps better handle date and time data in templates.

By using flexibilityintegerandfloatFilter, you can ensure accurate processing and display of numbers in the AnQiCMS template, thereby enhancing the robustness and user experience of the website.

Common Questions (FAQ)

Q1: What will I get if I convert a string that is not a number?

A1:If you try to convert a string that cannot be parsed as a number (such as “AnQiCMS”) to an integer or floating-point number,integerThe filter will return0,floatThe filter will return0.000000.This is a default error handling mechanism used to prevent template rendering interruption.When processing user input or other uncertain data, it is recommended to perform additional verification or default value setting on the converted results.

Q2: How to format a floating-point number to a specific decimal place, such as retaining two decimal places?

A2:After converting to a floating-point number, you can usefloatformata filter to control the display of decimal places. For example,{{ 您的浮点数 | floatformat:2 }}Will format floating-point numbers to two decimal places. If the number of digits is not specified, it will attempt to intelligently format, removing unnecessary trailing zeros.

Q3: Can the converted integer or floating-point number be used directly in mathematical operations and comparisons?

A3:Yes, once the numeric string has beenintegerorfloatFilter successfully converted to the corresponding numeric type, they can be used directly in template mathematical operations such as addition, subtraction, multiplication, and division, as well as size comparisons (for example,if item.Value > 10）、loop count and other numerical logic operations.