re = /\s?([+]\s?7|\s?8)(\s?[-]?\s?[(]?\s?\s?[)]?\s?[-]?\s?[0-9]\s?[-]?\s?[(]?\s?\s?[)]?\s?[-]?\s?){10}/m
str = '84951234567
+74951234567
8-495-1-234-567
8 (8122) 56-56-56
8-911-1234567
8 (911) 12 345 67
8-911 12 345 67
8 (911) - 123 - 45 - 67
+ 7 999 123 4567
8 ( 999 ) 1234567
8 999 123 4567
// выше - правильные, ниже - неправильные:
02
84951234567 позвать люсю
849512345
849512345678
8 (409) 123-123-123
7900123467
5005005001
8888-8888-88
84951a234567
8495123456a
+1 234 5678901
+8 234 5678901
7 234 5678901
'
subst = ''
result = str.gsub(re, subst)
# Print the result of the substitution
puts result
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html