用于替换SRC内容的正则表达式 <IMG> html标签

Question

我对正则表达式不太满意，因此我希望您能通过一个表达式来帮助我，以便仅替换html标记的src属性中双引号之间的内容，即该属性的内容如下：

TRegEx.Replace(Str, '(?<=<img\s+[^>]*?src=(?<q>[""]))(?<url>.+?)(?=\k<q>)', 'Nova string');

换句话说：src =“ old content ” => src =“ new content ”

我在上面有关C＃中相同主题的问题中已经看到了此表达式，但是不适用于Delphi。

那么，该怎么做呢？

提前谢谢。

Answer 1

正则表达式：

<img(.*?)src="(.*?)"(.*?)/>

替代：

<img$1src="NEW VALUE"$3/>

---

您可以使用类似：

var
    ResultString: string;

ResultString := '';
try
    ResultString := TRegEx.Replace(SubjectString, '<img(.*?)src="(.*?)"(.*?)/>', '<img$1src="NEW VALUE"$3/>', [roIgnoreCase, roMultiLine]);
except
    on E: ERegularExpressionError do begin
        // Syntax error in the regular expression
    end;
end;

---

正则表达式说明：

<img(.*?)src="(.*?)"(.*?)/>

Options: Case insensitive; Exact spacing; Dot doesn’t match line breaks; ^$ match at line breaks; Numbered capture; Allow zero-length matches

Match the character string “<img” literally (case insensitive) «<img»
Match the regex below and capture its match into backreference number 1 «(.*?)»
   Match any single character that is NOT a line break character (line feed, carriage return, form feed, vertical tab, next line, line separator, paragraph separator) «.*?»
      Between zero and unlimited times, as few times as possible, expanding as needed (lazy) «*?»
Match the character string “src="” literally (case insensitive) «src="»
Match the regex below and capture its match into backreference number 2 «(.*?)»
   Match any single character that is NOT a line break character (line feed, carriage return, form feed, vertical tab, next line, line separator, paragraph separator) «.*?»
      Between zero and unlimited times, as few times as possible, expanding as needed (lazy) «*?»
Match the character “"” literally «"»
Match the regex below and capture its match into backreference number 3 «(.*?)»
   Match any single character that is NOT a line break character (line feed, carriage return, form feed, vertical tab, next line, line separator, paragraph separator) «.*?»
      Between zero and unlimited times, as few times as possible, expanding as needed (lazy) «*?»
Match the character string “/>” literally «/>»

<img$1src="NEW VALUE"$3/>

Insert the character string “<img” literally «<img»
Insert the text that was last matched by capturing group number 1 «$1»
Insert the character string “src="NEW VALUE"” literally «src="NEW VALUE"»
Insert the text that was last matched by capturing group number 3 «$3»
Insert the character string “/>” literally «/>»

---

Regex101演示

Answer 2

解：

    procedure CHANGE_IMAGES(Document: IHTMLDocument2);
    var
      I: Integer;
      HTMLImgElement: IHTMLImgElement;
      HTMLElementCollection: IHTMLElementCollection;
    begin

      HTMLElementCollection := Document.images;

      for I := 0 to HTMLElementCollection.length - 1 do
      begin
        HTMLImgElement := (HTMLElementCollection.item(I, 0) as IHTMLImgElement);
        HTMLImgElement.src := 'My_IMAGE_PATH_OR_URL';
        Exit;
      end;
    end;