draw_string函数_PHP函数Is_string（）

淩亂°似流年 2022-12-06 15:23 159阅读 0赞

draw\_string函数

The **is\_string()** PHP function is used to check if a type of variable is a string. A string is a data type, such as floating point or integer, but it represents text rather than numbers. A string uses a set of characters that includes spaces and numbers. For instance, an address such as "1234 Broadway" and the sentence "I ate 3 hotdogs" contain numbers that should be treated as text, not as numbers.

PHP函数**is\_string()**用于检查变量的类型是否为字符串。 字符串是数据类型，例如浮点数或整数，但是它表示文本而不是数字。 字符串使用一组包含空格和数字的字符。 例如，一个地址(例如“ 1234 Broadway”)和句子“ I ate 3 hotdogs”包含应被视为文本而非数字的数字。

## 如何使用功能 **(** How to Use the Function **)** ##

Is\_string is used within an [if () statement][if _ statement] to treat strings in one way and non-strings in another. It returns true or false. For example:

在[if()语句中][if _ statement]使用Is\_string以一种方式处理字符串，以另一种方式处理非字符串。 它返回true或false。 例如：

<?php 
    if (is_string(23)) 
    {
        
    echo "Yes";
    } else {
        
    echo "No";
    }
    ?>

The code above should output "No" because 23 is not a string. Let's try this again:

上面的代码应该输出“ No”，因为23不是字符串。 让我们再试一次：

<?php 
    if (is_string("Hello World")) 
    {
        
    echo "Yes";
    } else {
        
    echo "No";
    }
    ?>

Since "[Hello World][]" is a string, this would echo "Yes."

由于“ [Hello World][] ”是字符串，因此将回显“是”。

## 指定一个字符串 **(** Specifying a String **)** ##

A string can be specified in four ways:

可以通过四种方式指定字符串：

*  Single quoted
    
    单引号
 *  Double quoted 
    
    双引号
 *  Heredoc syntax
    
    Heredoc语法
 *  Nowdoc Syntax
    
    Nowdoc语法

Each of these methods requires strict adherence to PHP rules, which are available at the PHP website. The simplest method, single-quoted strings, requires special treatment when literal single quotation marks or literal backslashes appear in the string. Include a backslash in front of the single quotation mark or backslash within the string. The example below illustrates this treatment:

这些方法中的每一种都必须严格遵守PHP规则，该规则可在PHP网站上获得。 最简单的方法，即单引号字符串，当在字符串中出现文字单引号或文字反斜杠时，需要进行特殊处理。 在单引号前面包括反斜杠，或者在字符串中包括反斜杠。 下面的示例说明了这种处理方法：

<?php
    // Outputs: Arnold said: "I'll be back"
    echo 'Arnold said: "I\'ll be back"';
    // Outputs: I deleted C:\*.*?
    echo 'I deleted C:\\*.*?';
    ?>

## 类似功能 **(** Similar Functions **)** ##

*  **is\_float()** – determines if the type of variable is float
    
    **is\_float()** –确定变量的类型是否为float
 *  **is\_int()** – determines if the type of variable is integer
    
    **is\_int()** –确定变量的类型是否为整数
 *  **is\_bool()** – determines if a variable is a boolean
    
    **is\_bool()** –确定变量是否为布尔值
 *  **is\_object()** – determines if a variable is an object
    
    **is\_object()** –确定变量是否为对象
 *  **is\_array()** – determines if a variable is an array
    
    **is\_array()** –确定变量是否为数组
 *  [**is\_numeric()**][is_numeric] – determines if a value is a number or a numeric string
    
    [**is\_numeric()**][is_numeric] –确定值是数字还是数字字符串

> 翻译自: [https://www.thoughtco.com/isstring-php-function-2694103][https_www.thoughtco.com_isstring-php-function-2694103]

draw\_string函数

[if _ statement]: https://www.thoughtco.com/beginners-guide-to-php-programing-2693961
[Hello World]: https://www.thoughtco.com/hello-world-2693946
[is_numeric]: https://www.thoughtco.com/isnumeric-php-function-2694075
[https_www.thoughtco.com_isstring-php-function-2694103]: https://www.thoughtco.com/isstring-php-function-2694103