I'm trying to ask a question on our friendly neighboring site, math.stackexchange.com and I'm new to mathjax and couldn't get what I need from this: https://math.meta.stackexchange.com/questions/5020/mathjax-basic-tutorial-and-quick-reference so I have come here for help.
I'm trying to show lambda is an element of the set (2,3) but I can't get the curly brackets/braces to be it. I can write it using parentheses, but not brackets (it makes a difference).
currently, I have $\lambda \in (2,3)$ but what I need are for those parentheses to be curly braces, and I can't figure it out.
Thanks!
MathJax is largely a subset of LaTeX, so when in doubt, refer to TeX documentation.
In this case, you need to know that curly braces are a common delimiter in TeX, and so they have to be escaped if you literally mean curly braces.
So, what you need is $\lambda \in \{ 2,3 \}$. Make sense?
Related
Sometimes, we put our bare "if" statements into the code without adding the curly braces if it is composed of only one expression. Unlike Sublime Code Completer, it is a hassle to put the enclosing parenthesis or curly braces around my statements in the Jetbrains Products. I mean
if (something)
statement
when I pressed to "{", I want for ide to put the enclosing one at the end of the statement instead of putting adjacent to the newly put opening one.
Not like this:
if (something) {}
statement
Intended form:
if (something){
statement
}
Is there a way to configure as wanted?
As far as I know, there is not a way to enclose a code block exactly the way you are looking for, but there is a similar feature available without too much more work. If you simply select the code you would like to wrap and enter an opening bracket, IntelliJ will wrap your code in the brackets and place both the brackets on their proper line given your coding style.
How to enclose curly braces in parenthesis in vim?
Initial string:
{a: b}
Final string:
({a: b})
The string possibly span multilines:
{
a: b
}
Assuming you are in normal mode and on any curly bracket character (opening or closing).
The manual/vanilla version (without any bracketing plugin) would be
c%(^R")
With:
^R meaning CTRL+R
the default register (") being filled with the content of the dictionary.
ca{ that should be used instead of c% if you're anywhere within the dictionary.
With my lh-brackets plugin, I would use v%( or vi{( -- unlike the vanilla version, will leave the default register unmodified.
With the popular surround plugin, I guess (I may be wrong as I've been using my plugin for decades) it would be something like ys%( or ysa{(.
PS: the fact your dictionary spans on several lines doesn't make any difference here.
With the vim-surround plugin you can visually select the text first e.g. va{, then surround with parentheses using S). I find it easier to remember this visual surround sequence v{motion}S<char> than the other options
str = "fa, (captured)[asd] asf, 31"
for word in str:gmatch("\(%a+\)") do
print(word)
end
Hi! I want to capture a word between parentheses.
My Code should print "captured" string.
lua: /home/casey/Desktop/test.lua:3: invalid escape sequence near '\('
And i got this syntax error.
Of course, I can just find position of parentheses and use string.sub function
But I prefer simple code.
Also, brackets gave me a similar error.
The escape character in Lua patterns is %, not \. So use this:
word=str:match("%((%a+)%)")
If you only need one match, there is no need for a gmatch loop.
To capture the string in square brackets, use a similar pattern:
word=str:match("%[(%a+)%]")
If the captured string is not entirely composed of letters, use .- instead of %a+.
lhf's answer likely gives you what you need, but I'd like to mention one more option that I feel is underused and may work for you as well. One issue with using %((%a+)%) is that it doesn't work for nested parentheses: if you apply it to something like "(text(more)text)", you'll get "more" even though you may expect "text(more)text". Note that you can't fix it by asking to match to the first closing parenthesis (%(([^%)]+)%)) as it will give you "text(more".
However, you can use %bxy pattern item, which balances x and y occurrences and will return (text(more)text) in this case (you'd need to use something like (%b()) to capture it). Again, this may be overkill for your case, but useful to keep in mind and may help someone else who comes across this problem.
I'm having a bit of trouble using parenthesis in a vim string. I just need to add a set of parenthesis around 3 digits, but I can't seem to find where I'm suppose to correctly place them. So for example; I would have to place them around a phone number such as: 2015551212.
Right now I have a strings that separates the numbers and puts a hyphen between them. For example; 201 555-1212. So I just need the parenthesis. The final result should look like: (201) 555-1212
The string I have so far is this: s/\(\d\{3}\)\(\d\{3}\)/\1 \2-/g
How might I go about doing this?
Thanks
Just add the parens around the \1 in your replacement.
s/\(\d\{3\}\)\(\d\{3\}\)/(\1) \2-/g
If you want to go in reverse, and change "(800) 555-1212" to "8005551212", you can use something like this:
s/(\(\d\d\d\))\ \(\d\d\d\)-\(\d\d\d\d\)/\1\2\3/g
Instead of the \d\d\d, you could use \d\{3\}, but that is more trouble to type.
OK, so here's an unusual one. Every time you see an example of Haskell's record syntax, it always looks like
Sphere {center = 0, radius = 2}
or similar. My question is... are those curly brackets actually part of the record syntax? Or are they actually shorthand for layout? In other words, can you actually write something like
Sphere
center = 0
radius = 2
and have it work?
I doubt it would be very useful to do this - it takes up a lot of visual space - but I'm just curious as to whether this is syntactically valid or not.
Layout is an alternative to explicit braces and semicolons.
Record syntax uses explicit braces and commas.
So no, you can't use layout as part of record syntax.
Haskell Report 2010 ยง2.7 Layout:
Haskell permits the omission of the braces and semicolons used in several grammar productions, by using layout to convey the same information.
OK, well I thought I'd put this question here in case anybody was interested. Having consulted the Haskell Report itself, it appears that the braces are literally a formal part of the record construct:
http://www.haskell.org/onlinereport/haskell2010/haskellch4.html#x10-690004.2.1
That means that these tokens actually have two distinct meanings in Haskell - as declaration delimiters when layout is not being used, and as record delimiters. I bet that leads to some interesting parser edge-cases!
(I also note in passing that EmptyDataDecls appears to be on by default in Haskell 2010, which is worth knowing...)
After Sphere, the lexer won't insert a brace. Why should it? You dont expect a brace inserted in code like:
z = x
+ y
either, do you?