What characters are allowed in an email address?
2010年1月12日 · All this control characters are allowed as stated at the start of section 3.5:.... MAY be used, the use of US-ASCII control characters (values 1 through 8, 11, 12, and 14 through 31) is discouraged .... And such an inclusion rule is therefore "just too wide". Or, in other sense, the expected rule is "too simplistic".
Which characters need to be escaped in HTML? - Stack Overflow
2011年9月12日 · Invisible or ambiguous characters: A particularly useful role for escapes is to represent characters that are invisible or ambiguous in presentation. One example would be Unicode character U+200F RIGHT-TO-LEFT MARK. This character can be used to clarify directionality in bidirectional text (eg. when using the Arabic or Hebrew scripts).
What is the difference between _tmain () and main () in C++?
2009年5月22日 · Since the compiler doesn't enforce this for the main function, you get a program where an array of wchar_t strings are passed to the main function, which interprets them as char strings. Now, in UTF-16, the character set used by Windows when Unicode is enabled, all the ASCII characters are represented as the pair of bytes \0 followed by the ...
Check for special characters (/*-+_@&$#%) in a string?
2010年12月21日 · If the list of acceptable characters is pretty small, you can use a regular expression like this: Regex.IsMatch(items, "[a-z0-9 ]+", RegexOptions.IgnoreCase); The regular expression used here looks for any character from a-z and 0-9 including a space (what's inside the square brackets []), that there is one or more of these characters (the ...
What should main () return in C and C++? - Stack Overflow
2008年10月15日 · If argc is nonzero these arguments shall be supplied in argv[0] through argv[argc-1] as pointers to the initial characters of null-terminated multibyte strings (NTMBSs) (17.5.2.1.4.2) and argv[0] shall be the pointer to the initial character of a NTMBS that represents the name used to invoke the program or "". The value of argc shall be non ...
How do I deal with special characters like \^$.?*|+ () [ { in my regex?
2014年12月31日 · To use special characters in a regular expression the simplest method is usually to escape them with a backslash, but as noted above, the backslash itself needs to be escaped. grepl("\\[", "a[b") ## [1] TRUE
Allowed characters in filename - Stack Overflow
2011年1月27日 · I took a different approach. Instead of looking if the string contains only valid characters, I look for invalid/illegal characters instead. NOTE: I needed to validate a path string, not a filename. But if you need to check a filename, simply add / to the set.
Select something that has more/less than x character
2016年8月31日 · Was wondering if it's possible to select something that has more/less than x characters in SQL. For example, I have an employee table and I want to show all employee names that has more than 4 characters in their name. Here's an example table. ID EmpName Dept 1 Johnny ACC 2 Dan IT 3 Amriel PR 4 Amy HR
javascript - Regex for password must contain at least eight …
2013年10月26日 · I had some difficulty following the most popular answer for my circumstances. For example, my validation was failing with characters such as ; or [. I was not interested in white-listing my special characters, so I instead leveraged [^\w\s] as a test - simply put - match non word characters (including numeric) and non white space characters. To ...
java - Take a char input from the Scanner - Stack Overflow
2012年12月19日 · Call next() on the Scanner, and extract the first character of the String (e.g. charAt(0)) If you want to read the rest of the line as characters, iterate over the remaining characters in the String. Other answers have this code.