Question

我尝试检查输入字符串是否为整数，但是没有任何东西返回我创建的模式的正结果。

#include <iostream>
#include <string>
#include <regex>
using namespace std;

int main()
{
    string input = "1";
    string int_num = "^0$|^[1-9][0-9]*$";

    regex pattern(int_num, regex_constants::grep);

    if(regex_match(input, pattern))
        cout << "matched\n";
    else
        cout << "not matched\n";

    return 0;
}

Answer 1

这对我有用，虽然根据ECMAScript正则表达式语法你的版本似乎也是正确的。

"^(0|[1-9][0-9]*)$"

Answer 2

您的模式不起作用的原因是因为您已指定正则表达式应模拟grep的语法。

如果从正则表达式定义中删除该标志，则您的模式可以正常工作：

string int_num = "^0$|^[1-9][0-9]*$";
regex pattern(int_num);

以下是修改过的脚本示例：https://ideone.com/iETnsw

如果必须指定正则表达式语法，请使用ECMAScript，而不是grep。

Answer 3

First of all, regex pattern should be changed to "^(0|[1-9][0-9]*)$" because it looks better. Then, change regex_constants::grep to regex_constants::ECMAScript, or leave blank, because ECMAScript is default. At the end, it is required to compile with g++-4.9, because g++-4.8 version doesn't work with regex lib.

Answer 4

使用Regex101.com，您可以判断您的表达式与数字不匹配。您可以使用表达式\d+来匹配数字。

另一种验证整数的方法是做这样的事情：

int y;
cin >> y;

if (cin.fail()) {
    //Is not an integer
}

Answer 5

我认为最好的方法是遍历每个字符以检查它们是否为数字，如果它到达结尾，那么它就是一个数字。也许会有所帮助。虽然没有测试过。

<?php if($aForm['sTaskType'] !== 'CP' ){?>
    <table style="width: 95%">
        <tr>
                <th>Area</th>
                <th>Pass</th>
                <th>Pass with feedback</th>
                <th>Fail with Minors</th>
                <th>Fail with Majors</th>
        </tr>

<?php  foreach ($aQualityTeamResults AS $iBusinessStreamId => $aTeamData) { 
$aQualityAgentResults = $oRadiusQualityFns->GetQualityAgentResults($sDateFrom, $sDateTo, $sTaskType, $aTeamData['iBusinessStreamId']);?>

        <tbody>
        <tr class="TeamClick<?php echo $iBusinessStreamId;?>">
            <td><?php echo $aTeamData['sBusinessStream']?></td>
            <td><?php echo $aTeamData['Pass']?></td>
            <td><?php echo $aTeamData['Pass with Feedback']?></td>
            <td><?php echo $aTeamData['Fail with Minors']?></td>
            <td><?php echo $aTeamData['Fail with Majors']?></td>
        </tr>
        </tbody>


            <?php  foreach ($aQualityAgentResults AS $iUserId => $aAgentData) { 
            $aQualityPropertyResults = $oRadiusQualityFns->GetQualityPropertyResults($sDateFrom, $sDateTo, $sTaskType, $aAgentData['iBusinessStreamId'], $aAgentData['Agent']);
            ?>
            <tbody>
            <tr  class="Agent<?php echo $iUserId; ?>">
            <td><?php echo $oRadiusUser->Get_User_Name($aAgentData['Agent']);?></td>
            <td><?php echo $aAgentData['Pass'];?></td>
            <td><?php echo $aAgentData['Pass with Feedback'];?></td>
            <td><?php echo $aAgentData['Fail with Minors'];?></td>
            <td><?php echo $aAgentData['Fail with Majors'];?></td>
            </tr>
            </tbody>

                <?php  foreach ($aQualityPropertyResults AS $iUserId2 => $aPropertyData) { ?>
                <tbody>
                <tr class="Property<?php echo $iUserId2 ;?>">
                <td colspan="2"><a href="<?echo $sPage?>?sPostPropertyCode=<?php echo $aPropertyData['sPropertyCode'];?>&sPostTaskType=<?php echo $aPropertyData['sTaskType'];?>&iPostUserId=<?php echo $iUserId;?>"><font color="black"><?php echo $aPropertyData['sPropertyCode']?></font></a></td>
                <td colspan="3"><?php echo $aPropertyData['Result']?></td>
                </tr>
                </tbody>
<?php 

                }
        }
}
?>  

</table>

Answer 6

您必须将语法规范删除为grep，然后才能正常工作。

int main（） { std :: string input =“1”;

    std::regex pattern ("^0$|^[1-9][0-9]*$");

      if(regex_match(input, pattern))
        cout << "matched\n";
    else
        cout << "not matched\n";

    return 0;
}

输出：匹配

整数匹配的正则表达式模式不起作用

6 个答案: