regex - 提取特定字符串后的数字

Question

我需要找到字符串“Count of”后面的数字。 “计数”字符串和数字之间可能有空格或符号。我有一些可以在 www.regex101.com 上运行的东西，但不能与 stringr str_extract 函数一起使用。

library(stringr)

shopping_list <- c("apples x4", "bag of flour", "bag of sugar", "milk x2", "monkey coconut 3oz count of 5", "monkey coconut count of 50", "chicken Count Of-10")
str_extract(shopping_list, "count of ([\\d]+)")
[1] NA NA NA NA "count of 5" "count of 50" NA

我想要得到什么:

[1] NA NA NA NA "5" "50" "10"

Answer 1

str_extract(shopping_list, "(?i)(?<=count of\\D)\\d+")
# [1] NA   NA   NA   NA   "5"  "50" "10"

哪里(?i)使模式不区分大小写，\\D表示不是数字，并且 ?<=是积极的回顾。