如果您只想在这些示例中匹配单词Color，则此正则表达式将起作用（运行示例以查看实际情况）/(?<=Title="[^"]*)\bColor\b(?=[^"]*")/g
故障：(?<=Title="[^"]*)：正向后查找，确保匹配前面有但不包括Title=”，后面有0个或多个非”字符
\bColor\b：匹配单词Color，但仅当它两边都有边界（不是数字或字母）时
(?=[^"]*")：积极的前瞻，确保匹配后面是但不包括任何数量的非“字符后面是一个”

const input = `<TocEntry
      Title="Color" - Highlight this text Color
Title=["Color"] - Ignore  this text Color
      Link="/Content/Color/" - ignore this text Color
      BreakType="Color" - ignore this text Color
      StartSection="false"
      PageNumberReset="Color"> - ignore this text Color
</TocEntry>
<TocEntry
      Title="Colord"> - ignore this text Colord
      //there could be Link="abc", BreakType="abc" here aswell
</TocEntry>
<TocEntry
      Title="dColord"> - ignore this text dColord
</TocEntry>

<TocEntry
      Title="my fav Color is red"> - Highlight this text Color
Title=["my fav Color is red"]> -  - ignore this text Color
</TocEntry>
<TocEntry
      Title="my fav 
Color 
is red"> - Highlight this text Color
</TocEntry>`

const matches = input.match(/(?<=Title="[^"]*)\bColor\b(?=[^"]*")/g)

console.log(matches)

console.log(input.replace(/(?<=Title="[^"]*)\bColor\b(?=[^"]*")/g, '[MATCHED AND REPLACED]'))

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这个正则表达式使用了单词边界

Title="([^"]*(\bcolor\b)[^"]*)"

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确保为不区分大小写设置“i”标志
工作示例：https://regex101.com/r/xlDpc2/1

试试这个

data="""<TocEntry
      Title="Color" - Highlight this text Color
Title=["Color"] - Ignore  this text Color
      Link="/Content/Color/" - ignore this text Color
      BreakType="Color" - ignore this text Color
      StartSection="false"
      PageNumberReset="Color"> - ignore this text Color
</TocEntry>
<TocEntry
      Title="Colord"> - ignore this text Colord
      //there could be Link="abc", BreakType="abc" here aswell
</TocEntry>
<TocEntry
      Title="dColord"> - ignore this text dColord
</TocEntry>

<TocEntry
      Title="my fav Color is red"> - Highlight this text Color
Title=["my fav Color is red"]> -  - ignore this text Color
</TocEntry>
<TocEntry
      Title="my fav 
Color 
is red"> - Highlight this text Color
</TocEntry>"""
def get_title_value(data):
     return re.findall(r'Title="(.*?\bColor\b.*?)"', data, flags=re.IGNORECASE)

print(get_title_value(data))

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产出：

['Color', 'my fav Color is red']

型