I want to remove all characters in a string that do not belong in a phone number string. The first character may or may not be a "+" and all other characters must be digits.
我想删除一个字符串中不属于电话号码字符串的所有字符。第一个字符可以是“+”，也可以不是“+”，所有其他字符都必须是数字。
I had gsub(/\D/, ''), but I want to keep the first character if it is a "+" (or a digit, of course). I then tried some negation, but this is not right, either: gsub(/^(\+?(\d))/, '').
我有gsub(/\D/，”)，但如果第一个字符是“+”(当然是数字)，我想保留它。然后我试过否定,但这是不正确的,要么:gsub(/ ^ \ + ?(\ d)/,”)。
How can I ignore the first character with regex iff it is a "+"?
我怎么可以忽略第一个字符的regex iff它是一个“+”?
2 个解决方案
#1
5
How about using a negative lookahead at the beginning:
开始时使用消极的展望:
gsub(/(?!^\+)\D*/, '')
Basically, the above regex should remove any series of non-digits where the first character is not a single '+' character at the beginning of the string.
基本上，上面的regex应该删除任何系列的非数字，其中第一个字符不是字符串开头的单个“+”字符。
Hope it helps.
希望它可以帮助。
#2
0
Unless you absolutely have to do it in one gsub, it might be simpler to pull the plus sign out separately. You could use the [] method, with something like:
除非你必须在一个gsub中完成它，否则把加号单独拉出来可能会更简单。您可以使用[]方法，例如:
my_string[/^\+/].to_s + my_string.gsub(/\D/, '')
my_string[/ ^ \ + /]。to_s + my_string。gsub(\ D /”)
The to_s is necessary since the method will return nil if the plus sign isn't found.
to_s是必需的，因为如果没有找到加号，方法将返回nil。
#1
5
How about using a negative lookahead at the beginning:
开始时使用消极的展望:
gsub(/(?!^\+)\D*/, '')
Basically, the above regex should remove any series of non-digits where the first character is not a single '+' character at the beginning of the string.
基本上，上面的regex应该删除任何系列的非数字，其中第一个字符不是字符串开头的单个“+”字符。
Hope it helps.
希望它可以帮助。
#2
0
Unless you absolutely have to do it in one gsub, it might be simpler to pull the plus sign out separately. You could use the [] method, with something like:
除非你必须在一个gsub中完成它，否则把加号单独拉出来可能会更简单。您可以使用[]方法，例如:
my_string[/^\+/].to_s + my_string.gsub(/\D/, '')
my_string[/ ^ \ + /]。to_s + my_string。gsub(\ D /”)
The to_s is necessary since the method will return nil if the plus sign isn't found.
to_s是必需的，因为如果没有找到加号，方法将返回nil。