如何找到文本中匹配单词的索引？

Question

我正在提取与此正则表达式匹配的单词的索引。 它使用正则表达式匹配文本中所有必需的单词，但也匹配正则表达式的剩余空间。 它不限制左侧文本中的匹配字符串，而是使用\\b匹配字符串的右侧

正则表达式：

(price|rs)?\s*(\d+[\s\d.]*\s*?(pkg|k|m|(?:la(?:c|kh|k)|crore|cr)s?|l)\b\.?)

输入文本：

    This should matchprice  5.6 lacincluding price(i.e  price 5.6 lac) and rs 56 m. including rs (i.e rs 56 k  rs 56 m) .

It will match normally if there is no price or rs written for example or                   56 k or   8.8 crs.   are  correct matching but its should bound the matched string from left side as well just like its not matching sapce after end of the matched string.

It should not match the spaces left of 8.5 in this      8.5 lac ould not match eitherrs 6 lac asas there is no spaces before 5.6

How can I modify above regex to bound the matched word in the left side as well? 

Answer 1

您可以将\\s*移至可选的非捕获组：

(?:\b(price|rs)\s*)?(\d+[\s\d.]*\s*?(pkg|k|m|(?:la(?:c|kh|k)|crore|cr)s?|l)\b\.?)
^^^^^^^^^^^^^^^^^^^^

见正则表达式演示

(?:\\b(price|rs)\\s*)? pattern将匹配单词边界，后跟price或rs ，后跟0+空格字符，整个模式将尝试一次，并且由于? ，该模式是可选的 修饰符（图案的整个序列可以匹配1或0次）