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PHP parses strings into variables based on the format string function sscanf()

黄舟Original: 2017-11-03 09:54:241819browse

Example

Parse a string:

sscanf() function parses input from a string according to the specified format. The sscanf() function parses a string into a variable based on a format string.

If only two parameters are passed to this function, the data will be returned in the form of an array. Otherwise, if additional parameters are passed, the parsed data will be stored in these parameters. If the number of separators is greater than the number of variables containing them, an error occurs. However, if the number of separators is less than the number of variables that contain them, the extra variables contain NULL.

Related functions:

printf() - Outputs a formatted string
sprintf() - Write a formatted string into a variable

Syntax

sscanf(string,format,arg1,arg2,arg++)

arg1Optional. The first variable to store data. arg2Optional. A second variable to store the data. arg++Optional. The third and fourth variables that store data. So on and so forth.

技术细节

Parameters	Description
string	Required. Specifies the string to be read.
format	Required. Specifies the format to be used. Possible format values: %% - Returns a percent sign % %c - The character corresponding to the ASCII value %d - Decimal number with sign (negative, 0, positive) %e - Use lowercase scientific notation (For example, 1.2e+2) ##%u - Decimal number without sign (greater than or equal to 0) %f - Floating point number %o - Octal number %s - String %x - Hexadecimal number (lower case letters) %X - Hexadecimal number (upper case letters) Additional format value . Must be placed between % and a letter (e.g. %.2f): + (Add + or - in front of a number to define the sign of the number. By default, only Negative numbers are marked, positive numbers are not marked) ' (Specifies what to use as padding, the default is spaces. It must be used with the width specifier. For example: %'x20s ( Use "x" as padding)) - (Adjust the variable value left) [0-9] (Specify the minimum variable value Width) .[0-9] (Specifies the number of decimal places or the maximum string length) Comments : If multiple above format values are used, they must be used in the order above and cannot be disrupted.

返回值：	如果只向该函数传递两个参数，数据将以数组的形式返回。否则，如果传递了额外的参数，那么被解析的数据会存储在这些参数中。如果区分符的数目大于包含它们的变量的数目，则会发生错误。不过，如果区分符的数目小于包含它们的变量的数目，则额外的变量包含 NULL。
PHP 版本：	4.0.1+

更多实例

实例 1

使用格式值 %s、%d 和 %c：

sscanf() 的作用：从一个字符串中读进与指定格式相符的数据.

原型: int sscanf (const char *str,const char * format,........);

说明： sscanf()会将参数str的字符串根据参数format字符串来转换并格式化数据。转换后的结果存于对应的参数内。

成功则返回参数数目，失败则返回0。

注意：sscanf与scanf类似，都是用于输入的，只是后者以键盘(stdin)为输入源，前者以固定字符串为输入源。

大家都知道sscanf是一个很好用的函数，利用它可以从字符串中取出整数、浮点数和字符串等等。它的使用方法简单，特别对于整数和浮点数来说。

这里就举几个经常用到的例子来说明他的用法，便于大家深刻理解他的用法.

例子：

#include  
#include  
#include  
  
int main(){  
    char str[100];  
    //用法一：取指定长度的字符串  
    sscanf("12345","%4s",str);  
    printf("用法一\nstr = %s\n",str);  
  
    //用法二：格式化时间  
    int year,month,day,hour,minute,second;  
    sscanf("2013/02/13 14:55:34","%d/%d/%d %d:%d:%d",&year,&month,&day,&hour,&minute,&second);  
    printf("用法二\ntime = %d-%d-%d %d:%d:%d\n",year,month,day,hour,minute,second);  
  
    //用法三：读入字符串  
    sscanf("12345","%s",str);  
    printf("用法三\nstr = %s\n",str);  
  
    //用法四：%*d 和 %*s 加了星号 (*) 表示跳过此数据不读入. (也就是不把此数据读入参数中)  
    sscanf("12345acc","%*d%s",str);  
    printf("用法四\nstr = %s\n",str);  
  
    //用法五：取到指定字符为止的字符串。如在下例中，取遇到'+'为止字符串。  
    sscanf("12345+acc","%[^+]",str);  
    printf("用法五\nstr = %s\n",str);  
  
    //用法六：取到指定字符集为止的字符串。如在下例中，取遇到小写字母为止的字符串。  
    sscanf("12345+acc121","%[^a-z]",str);  
    printf("用法六\nstr = %s\n",str);  
    return 0;  
}

PHP parses strings into variables based on the format string function sscanf()

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