If I have a string like "Fuel & Additives" when my XML parser goes through it ignores anything BEFORE the "&" symbol, why?
if ([elementname isEqualToString:#"GLDesc"])
{
currentParsedObjectContainer.GLDesc = currentNodeContent;
NSLog(#"%#",currentParsedObjectContainer.GLDesc);
}
The ampersand character (&) and the
left angle bracket (<) may appear in
their literal form only when used as
markup delimiters, or within a
comment, a processing instruction, or
a CDATA section. If they are needed
elsewhere, they must be escaped using
either numeric character references or
the strings "&" and "<"
respectively.
http://www.w3.org/TR/2000/REC-xml-20001006#syntax
As the above snippet states, you'll need to escape & to the string & before passing it to the XML parser.
I'm going to say it has something to do with character codes (for example <). I'm not really familiar with xml though, so I'm not sure. Try &?
Related
I tried many ways to get a single backslash from an executed (I don't mean an input from html).
I can get special characters as tab, new line and many others then escape them to \\t or \\n or \\(someother character) but I cannot get a single backslash when a non-special character is next to it.
I don't want something like:
str = "\apple"; // I want this, to return:
console.log(str); // \apple
and if I try to get character at 0 then I get a instead of \.
(See ES2015 update at the end of the answer.)
You've tagged your question both string and regex.
In JavaScript, the backslash has special meaning both in string literals and in regular expressions. If you want an actual backslash in the string or regex, you have to write two: \\.
The following string starts with one backslash, the first one you see in the literal is an escape character starting an escape sequence. The \\ escape sequence tells the parser to put a single backslash in the string:
var str = "\\I have one backslash";
The following regular expression will match a single backslash (not two); again, the first one you see in the literal is an escape character starting an escape sequence. The \\ escape sequence tells the parser to put a single backslash character in the regular expression pattern:
var rex = /\\/;
If you're using a string to create a regular expression (rather than using a regular expression literal as I did above), note that you're dealing with two levels: The string level, and the regular expression level. So to create a regular expression using a string that matches a single backslash, you end up using four:
// Matches *one* backslash
var rex = new RegExp("\\\\");
That's because first, you're writing a string literal, but you want to actually put backslashes in the resulting string, so you do that with \\ for each one backslash you want. But your regex also requires two \\ for every one real backslash you want, and so it needs to see two backslashes in the string. Hence, a total of four. This is one of the reasons I avoid using new RegExp(string) whenver I can; I get confused easily. :-)
ES2015 and ES2018 update
Fast-forward to 2015, and as Dolphin_Wood points out the new ES2015 standard gives us template literals, tag functions, and the String.raw function:
// Yes, this unlikely-looking syntax is actually valid ES2015
let str = String.raw`\apple`;
str ends up having the characters \, a, p, p, l, and e in it. Just be careful there are no ${ in your template literal, since ${ starts a substitution in a template literal. E.g.:
let foo = "bar";
let str = String.raw`\apple${foo}`;
...ends up being \applebar.
Try String.raw method:
str = String.raw`\apple` // "\apple"
Reference here: String.raw()
\ is an escape character, when followed by a non-special character it doesn't become a literal \. Instead, you have to double it \\.
console.log("\apple"); //-> "apple"
console.log("\\apple"); //-> "\apple"
There is no way to get the original, raw string definition or create a literal string without escape characters.
please try the below one it works for me and I'm getting the output with backslash
String sss="dfsdf\\dfds";
System.out.println(sss);
We are getting a value from a DB that contains a backslash (\). After going through DataWeave, we get 2 backslashes. Here it is how it looks:
How can we have only one backslash in the end? Can we use the replace function somehow? I tried and could not make it work.
I believe the reason why you see two backslashes is because backslash is a reserved character (see JSON spec) therefore DataWeave is automatically escaping the backslash, which is necessary so not to have your DB value corrupted.
In my opinion the double backslash is not a problem. You should get the right content upon consuming the JSON object.
You could try to put in an escape character of your choice
Eg: %output application/csv escape = " "
This should ideally replace "/" with " ".
Hope this helps.
In VB.NET how do I replace special opening and closing double quotes (“ and ”) with ASCII quotes (").
Ive tried
s = s.replace("“", """")
but it seems that Visual Studio consider the “ quote in my code to be a normal quote leaving me with an invalid statement.
Unfortunately VB.NET doesn't support escape sequences but you can use ChrW() to specify code point:
s = s.Replace(ChrW(&H201C), """")
That's for “, code for ” is &H201D. Note that using code points you're free to search & replace any Unicode character (not just what VB.NET has an escape for - like ").
For complete list see: http://unicode-table.com/en/
If you want to use a quotation mark inside a string, VB doesn’t know whether the quotation mark is supposed to end the string or not. In C#, this would be fixed by escaping the quotation mark, i.e. in place of """ you’d write "\"". In VB, the same is done by doubling the quotation mark, i.e. """".
Back to your curly quote. The same as for straight quotes applies according to the VB language specification (¶1.6.4). So to write a curly quote in code, try the following:
s = Replace(s , "““", "“")
a second way: s = Replace(s , ChrW(&H201C), "“")
I am parsing XML Data using NSXMLParser and I notice now, that the Elements can contain ALL characters, including for example a &. Since the parser is giving an error when it comes across this character I replaced every Occurence of this character.
Now I want to make sure to handle every of these characters that may cause Errors.
What are they and how do you think I should handle these characters best?
Thanks in advance!
To answer half your question, XML has 5 special characters that you may want to escape:
< -- replace with <
> -- replace with >
& -- replace with &
' -- replace with '
and
" -- replace with "
Now, for the other half--how to find and replace these without also replacing all the tags, etc... Not easy, but I'd look in to regular expressions and NSRegularExpression: http://developer.apple.com/library/ios/#documentation/Foundation/Reference/NSRegularExpression_Class/Reference/Reference.html
Remember, depending on your use case, to escape the values of the parameters on tags, too; <tag parameter="with "quotes"" />
You should encode these characters for instance & becomes & or " becomes "
When it goes through the parser it should come out ok. Your other option is to use a different XML parser like TBXML which doesn't do format checking.
I need a complete list of characters that should be escaped in sql string parameters to prevent exceptions. I assume that I need to replace all the offending characters with the escaped version before I pass it to my ObjectDataSource filter parameter.
No, the ObjectDataSource will handle all the escaping for you. Any parametrized query will also require no escaping.
As others have pointed out, in 99% of the cases where someone thinks they need to ask this question, they are doing it wrong. Parameterization is the way to go. If you really need to escape yourself, try to find out if your DB access library offers a function for this (for example, MySQL has mysql_real_escape_string).
SQL Books online:
Search for String Literals:
String Literals
A string literal consists of zero or more characters surrounded by quotation marks. If a string contains quotation marks, these must be escaped in order for the expression to parse. Any two-byte character except \x0000 is permitted in a string, because the \x0000 character is the null terminator of a string.
Strings can include other characters that require an escape sequence. The following table lists escape sequences for string literals.
\a
Alert
\b
Backspace
\f
Form feed
\n
New line
\r
Carriage return
\t
Horizontal tab
\v
Vertical tab
\"
Quotation mark
\
Backslash
\xhhhh
Unicode character in hexadecimal notation
Here's a way I used to get rid of apostrophes. You could do the same thing with other offending characters that you run into. (example in VB.Net)
Dim companyFilter = Trim(Me.ddCompany.SelectedValue)
If (Me.ddCompany.SelectedIndex > 0) Then
filterString += String.Format("LegalName like '{0}'", companyFilter.Replace("'", "''"))
End If
Me.objectDataSource.FilterExpression = filterString
Me.displayGrid.DataBind()