I need to generate things like"
F||;||(,t,t)".
I try parse("F__||;|(,t,t)"). Maple returns "Error, incorrect syntax in parse: ; unexpected (near 6th character of parsed string)"
Is there any way to get this F||;||(,t,t)"?
To create names with special characters, you need to use single back quotes (also known as accent grave), which is the character under escape on most US keyboards.
parse("`F__||;||`(``,t,t)");
Related
I am working on string manipulation using LUA and having trouble with the following problem.
Using this as an example of the original data I am given -
"[0;1;36m(Web): You say, "Text here."[0;37m"
I want to keep the string intact except for removing the ANSI codes.
I have been pointed toward using gsub with the LUA pattern matching but I cannot seem to get the pattern correct. I am also unsure how to reference exactly the escape character sent.
text:gsub("[\27\[([\d\;]+)m]", "")
or
text:gsub("%x%[[%d+;+]m", "")
If successful, all I want to be left with, using the above example, would be:
(Web): You say, "Text here."
Your string example is missing the escape character, ASCII 27.
Here's one way:
s = '\x1b[0;1;36m(Web): You say, "Text here."\x1b[0;37m'
s = s:gsub('\x1b%[%d+;%d+;%d+;%d+;%d+m','')
:gsub('\x1b%[%d+;%d+;%d+;%d+m','')
:gsub('\x1b%[%d+;%d+;%d+m','')
:gsub('\x1b%[%d+;%d+m','')
:gsub('\x1b%[%d+m','')
print(s)
I'm receiving a string from the server and it has the special characters in code. Here's the example:
"El usuario o las contrase\UOOOOfffda no son v\UOOOOfffdlidos"
The first one should be an "ñ" and the second one "á"
I know it's not complicated but I can't find the answer. How can I get the string with the special characters correctly formatted?
Unicode U+FFFD (in your string, displayed as UTF-32 \U0000fffd) is "�", the replacement character. It is often substituted in strings when a system encounters unrecognized characters.
This character really shouldn't appear in string data since its purpose is to indicate an error in displaying or interpreting the string. Since your server is sending you that character for both ñ and á, there is no way to retrieve the correct character.
How are you "receiving" this string? It could be that you are accessing the server incorrectly so it isn't sending you an unmodified string.
Unicode for those characters should look like this:
#"accented-a is \u00f1, and tilda-n is \u00e1"
But it's not clear what you're getting from the server makes any sense. The objective-c literal must have a lowercase leading "u" followed only by valid hex digits (0-9 and a-f). I don't see a transformation that changes the literals you have to the ones you expect.
Once the characters are formatted properly, the built-in classes will just work, for example, assigning the string to a label's text property will show the user a nice glyph.
Is there a way to convert a quoted string to a multiline string?
Something like "This string \66 here" to [[This string \66 here]] since I would like to ignore the interpretation of escaped characters.
Lua 5.3 Reference Manual 3.1: Lexical Conventions
Literal strings can also be defined using a long format enclosed by
long brackets. We define an opening long bracket of level n as an
opening square bracket followed by n equal signs followed by another
opening square bracket. So, an opening long bracket of level 0 is
written as [[, an opening long bracket of level 1 is written as [=[,
and so on. A closing long bracket is defined similarly; for instance,
a closing long bracket of level 4 is written as ]====]. A long literal
starts with an opening long bracket of any level and ends at the first
closing long bracket of the same level. It can contain any text except
a closing bracket of the same level. Literals in this bracketed form
can run for several lines, do not interpret any escape sequences, and
ignore long brackets of any other level. Any kind of end-of-line
sequence (carriage return, newline, carriage return followed by
newline, or newline followed by carriage return) is converted to a
simple newline.
For convenience, when the opening long bracket is immediately followed
by a newline, the newline is not included in the string.
That's all you need to know about long strings.
It does not make much sense to convert a string that has been defined using quotes "some string" to a string like [[some string]] as both quotes and square brackets are not actually part of that string and the string itself is the same.
The only difference would be a leading newline which is ignored in square brackets or escape sequences which are not interpreted.
Quotes and square brackets are only part of the string if you have nested strings. In this case conversion also doesn't make much sense because you cannot nest strings with quotes like strings with brackets.
Maybe your whole approach is a bit off?
Do you look for something like this?
local db = "google"
local tbl = "accounts"
local where = "field = 'VALUE' AND TRUE"
local order = "id DESC"
local query = string.format([[
SELECT *
FROM `%s`.`%s`
WHERE %s
ORDER BY %s
]], db, tbl, where, order)
I'm trying to create a regular expression string that will capture the data between the opening and closing [] brackets and include the brackets from the following data:
data: [{"LOTS OF DATA}],
datatype: "local",
So far I'm using a regEx string "data:(.*)" and this is returning:
[{"LOTS OF DATA}],
This is almost correct but includes the ',' and the reason this is working is because theres a newline or carriage return before 'datatype:' So I have two questions:
How do I capture all characters including the newline & carriage return?
How do I match the ', datatype:' string. The issue with this is that I cannot guarantee the character type and number of characters between the ',' and 'datatype:' string, I need a wild card? The regEx string would look something like "data:(.*),???datatype:" where ??? is the wildcard?
Thanks for your help, this will be used within an iOS application.
data:\s*\[([^\[\]]*)\]\s*,\s*datatype:
This implies that no square brackets may occur within LOTS OF DATA.
You could even spare the trailing 'datatype:' match.
Should LOTS OF DATA contains square brackets you would have to come up with a more precise specification of its content.
Could anybody help me make a proper regular expression from a bunch of text in Ruby. I tried a lot but I don't know how to handle variable length titles.
The string will be of format <sometext>title:"<actual_title>"<sometext>. I want to extract actual_title from this string.
I tried /title:"."/ but it doesnt find any matches as it expects a closing quotation after one variable from opening quotation. I couldn't figure how to make it check for variable length of string. Any help is appreciated. Thanks.
. matches any single character. Putting + after a character will match one or more of those characters. So .+ will match one or more characters of any sort. Also, you should put a question mark after it so that it matches the first closing-quotation mark it comes across. So:
/title:"(.+?)"/
The parentheses are necessary if you want to extract the title text that it matched out of there.
/title:"([^"]*)"/
The parentheses create a capturing group. Inside is first a character class. The ^ means it's negated, so it matches any character that's not a ". The * means 0 or more. You can change it to one or more by using + instead of *.
I like /title:"(.+?)"/ because of it's use of lazy matching to stop the .+ consuming all text until the last " on the line is found.
It won't work if the string wraps lines or includes escaped quotes.
In programming languages where you want to be able to include the string deliminator inside a string you usually provide an 'escape' character or sequence.
If your escape character was \ then you could write something like this...
/title:"((?:\\"|[^"])+)"/
This is a railroad diagram. Railroad diagrams show you what order things are parsed... imagine you are a train starting at the left. You consume title:" then \" if you can.. if you can't then you consume not a ". The > means this path is preferred... so you try to loop... if you can't you have to consume a '"' to finish.
I made this with https://regexper.com/#%2Ftitle%3A%22((%3F%3A%5C%5C%22%7C%5B%5E%22%5D)%2B)%22%2F
but there is now a plugin for Atom text editor too that does this.