Question

我需要两个正则表达式，匹配任何以10PL结尾的(a single whitespace) (any integer) (the string PL in caps) (line terminates)。我尝试了以下但没有一个有效。例如。

var str="Visit W3Schools 45PL";  // should match this
var str1="Visit W3Schools 45PL Other";  // should NOT match this
var str2 = "Any Random value 133PL" // should match this
var str3 = "Any Random value 133Pl" // should NOT match this

其他应与21.323X230 (a single whitespace) (any floating value) (the word X in caps) (any other floating point value) (line terminates)匹配。例如。

var test="Visit W3Schools 4X5";  // should match this
var test1="Visit W3Schools 4X5PL Other";  // should NOT match this
var test2 = "Any Random value 13.270X46.96" // should match this
var test3 = "Any Random value 13.21X12.36 " // should NOT match this, as last word is white space

我尝试了以下模式（第一个模式（PL一个））。

var patt1=/\s+\d+/PL/g;
var patt2 = /[ ]+[0-9]+/PL/g;
document.write(patt1.test(str));
document.write(patt2.test(str));
document.write(patt1.test(str1));
document.write(patt2.test(str1));
document.write(patt1.test(str2));
document.write(patt2.test(str2));
document.write(patt1.test(str3));
document.write(patt2.test(str3));

结果全为空（document.write没有写任何东西）。那么，任何人都可以帮我找出这两种模式的正则表达式吗？

Answer 1

您的模式中存在语法错误 - 正则表达式中间的/是

不需要（没有你想要匹配的文字斜杠，是吗？）和
混淆正则表达式引擎，因为它将其解释为结束正则表达式分隔符。然后它尝试将PL/g解释为正则表达式修饰符（当然这不起作用）。

另外，你并没有告诉正则表达式它只应该在一行的末尾匹配该模式。所以试试这个：

var patt1 = / \d+PL$/gm;

$匹配（与m修饰符一起）一行的结尾。如果没有该修饰符，它只会匹配字符串的结尾。

对于第二个：

var patt2 = / \d+(?:\.\d+)?X\d+(?:\.\d+)?$/gm;

另外，请不要visit W3Schools。这是互联网上最错误的地方之一。如果您不相信我，请查看http://w3fools.com。

Answer 2

这应该这样做。

var str  = "Visit W3Fools 45PL";          // should match this
var str1 = "Visit W3Fools 45PL Other";    // should NOT match this
var str2 = "Any Random value 133PL"       // should match this
var str3 = "Any Random value 133Pl"       // should NOT match this

var test  = "Visit W3Fools 4X5";              // should match this
var test1 = "Visit W3Fools 4X5PL Other";      // should NOT match this
var test2 = "Any Random value 13.270X46.96";  // should match this
var test3 = "Any Random value 13.21X12.36 ";  // should NOT match this, as last word is white space

var patt1 = /\s\d+PL$/;

document.write( patt1 + ' =~ "' + str + '" => ' + patt1.test(str) + '<br>');
document.write( patt1 + ' =~ "' + str1 + '" => ' + patt1.test(str1) + '<br>');
document.write( patt1 + ' =~ "' + str2 + '" => ' + patt1.test(str2) + '<br>');
document.write( patt1 + ' =~ "' + str3 + '" => ' + patt1.test(str3) + '<br>');

var patt2 = /\s\d+(?:[.]\d+)?X\d+(?:[.]\d+)?$/;

document.write( patt2 + ' =~ "' + test + '" => ' + patt2.test(test) + '<br>');
document.write( patt2 + ' =~ "' + test1 + '" => ' + patt2.test(test1) + '<br>');
document.write( patt2 + ' =~ "' + test2 + '" => ' + patt2.test(test2) + '<br>');
document.write( patt2 + ' =~ "' + test3 + '" => ' + patt2.test(test3) + '<br>');

该页面写为：

/\s\d+PL$/ =~ "Visit W3Fools 45PL" => true
/\s\d+PL$/ =~ "Visit W3Fools 45PL Other" => false
/\s\d+PL$/ =~ "Any Random value 133PL" => true
/\s\d+PL$/ =~ "Any Random value 133Pl" => false
/\s\d+(?:[.]\d+)?X\d+(?:[.]\d+)?$/ =~ "Visit W3Fools 4X5" => true
/\s\d+(?:[.]\d+)?X\d+(?:[.]\d+)?$/ =~ "Visit W3Fools 4X5PL Other" => false
/\s\d+(?:[.]\d+)?X\d+(?:[.]\d+)?$/ =~ "Any Random value 13.270X46.96" => true
/\s\d+(?:[.]\d+)?X\d+(?:[.]\d+)?$/ =~ "Any Random value 13.21X12.36 " => false

给定模式的正则表达式？

2 个答案: