I am confused as to why I am capturing this pattern via '
I am confused as to why I am capturing this pattern via '\1' grouping. I am capturing two digits at a time, but why does it skip here:
我很困惑为什么我通过'\ 1'分组捕获这个模式。我一次捕获两位数，但为什么跳过这里：
"123 456 789".gsub(/(\d)(\d)/, '\1')
=> "13 46 79"
I can understand that '\0' gives me the original string:
我能理解'\ 0'给了我原始的字符串：
"123 456 789".gsub(/(\d)(\d)/, '\0')
=> "123 456 789"
This also confuses me, but I can understand '\2' once I learn what '\1' is doing:
这也让我感到困惑，但是一旦我知道'\ 1'正在做什么，我就能理解'\ 2'：
"123 456 789".gsub(/(\d)(\d)/, '\2')
=> "23 56 89"
2 个解决方案
#1
4
The regex matches "12", "45", "78", and gsub replaces them with "1", "4", "7", respectively, giving "13 46 79".
正则表达式匹配“12”，“45”，“78”，并且gsub分别用“1”，“4”，“7”替换它们，给出“13 46 79”。
#2
2
To obtain 12 45 78, you need to use
要获得12 45 78，您需要使用
(\d)\d\b
And replace with \1.
并替换为\ 1。
See demo
见演示
Here, we match a digit and capture it ((\d)), then we match another digit (with \d) that is right before a word boundary \b.
在这里，我们匹配一个数字并捕获它（（\ d）），然后我们匹配在字边界\ b之前的另一个数字（\ d）。
IDEONE演示：
puts "123 456 789".gsub(/(\d)\d\b/, '\1')
' grouping. I am capturing two digits at a time, but why does it skip here:I am confused as to why I am capturing this pat
