re = /\+?|0*|(972)?(.*)/
str = '0527691234
00527691234
527691234
00972527691234
972527691234
+972527691234
'
subst = '$2'
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