i tried to do to remove special characters in string
--repeating-repeating
What i want is that the string would become
repeating-repeating
I used string operations and replace in strings, but it would remove all the dash line -
What should i do then?
You can use a “replace in string” step, with option “use Regex” set to Y.
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);
In Pentaho data-integration I need (from a Excel Input) to replace a specific string.
I need to delete all characters after the first comma (it can be in a casual position), like this:
"A,b,c,f" -> "A"
"aaaaa,bbbb,cccc" -> "aaaaa"
I've tried string cut but it allows meto cut after a specific number of characters (not a specific word or character, such as comma).
In my sql is : SUBSTRING_INDEX(technician, ',', 1).. but what would it be with Pentaho?
Thanks
You can use the Replace in strings step, set it to search and replace using RegEx, set the search RegEx to ([^,]),. and set the replace field as $1.
I want to exclude spaces when validating a textbox in vb.net.
Here is the current ValidationExpressopn value:
ValidationExpression="^([a-zA-Z0-9_-.\']+)#(([[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.)|(([a-zA-Z0-9-]+.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(]?)$" />
When user inputs space in textbox, I dont want that to render as error.
Example: I include spaces after "1#test.com "
This should not be treater as incorrect data in the textbox.
Any ideas?
If your spaces are leading or trailing you can do a Trim on the expressionToValidate before comparing to your regexp
Dim expressionWithoutTrailingAndLeadingWhiteSpaces As String = originalExpression.Trim()
If you want to modify the regExp to take into account the trailing spaces:
^[_a-z0-9-]+(.[a-z0-9-]+)#[a-z0-9-]+(.[a-z0-9-]+)*(.[a-z]{2,4})( *)$
If you want to exclude also leading spaces add an extra ( *) at the beginning of the expression:
^( *)[_a-z0-9-]+(.[a-z0-9-]+)#[a-z0-9-]+(.[a-z0-9-]+)*(.[a-z]{2,4})( *)$
Btw - the regExp you are providing is broken - I used the one found here (expression to validate email addresses)
examples:
"""Romeo and Juliet"""
'another string that is quoted with '' single quotes'
the problem is that the string can have characters used for db escaping even in it's beginning and end, so regex should look if given char is used in sequence of odd length that is 1,3,5... at the end of matched string
Try this regex: '(?:[^']|'')*' for single quotes. The same for double quotes, i.e. full regex:
'(?:[^']|'')*'|"(?:[^"]|"")*"
In string hello 'my ''beautiful''' 'world'! """Romeo and Juliet""" it will find:
'my ''beautiful'''
'world'
"""Romeo and Juliet"""
Where your string includes (or might include) characters that cause problems in your sql, you should always escape.
If you're using PHP with a mysql database, use mysql_real_escape_string($text); (docs)
For other databases and languages, you'll have to check for your specific purposes, but there's likely to be an existing method.
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()