I'm extremely new at Perl and trying to prove I can pick it up quickly. What I was asked to do is add a string as an argument on my command line, and then feed that into my script. From there it is supposed to search a MySQL table I've made for matches in one column, and spit the contents of another column into an array. It was suggested I used the Getops:Std but I'm uncertain how exactly to do that, and if that's the best technique.
For example: I have a MySQL table with car manufacturers, and car models. I want to run, Perl myscript.pl Ford, and then have it shoot me back an array with
Mustang
Escape
Focus
But I'm uncertain how to get that string input in the first place. Would Getops:Std be best? If so how would it be written? I'm picking this up quickly, but I've been at it less than a week, so the simpler the explanation, the better.
Edit: Basically I was confused why it was suggested I should use GetOpts::Std for this. It seems to be completely inappropriate for what I'm trying to do.
GetOpts::Std is overkill for this. Your command line arguments are in #ARGV. If you haven't been able to work that out after a week, then you need better references for Perl.
The first argument will be in $ARGV[0], the second in $ARGV[1] , and so on.
You should check the DBI module. Google for some tutorial out there.
Then try to write your script and post more specific questions with some code if you need more help.
Related
Long time lurker, first time poster.
I'm trying to write a vscode syntax for TeraTerm (ttl), of which has been quite the learning experience, and have hit a few walls. Biggest problem I have is writing a regex for ttl's if/then/endif. Normally I enjoy the satisfaction of figuring things out for myself, but every time I mess up on this I end up locking things up pretty hard. ttl's format for if then is:
if expression then
statement
elseif expression then
statement
endif
A single if/then is easy to work out in tmlanguage, but putting a regex together for nested if/thens has resulted in several ctrl-alt-deletes. I've gotten pretty good at lookaheads/behinds within a single line, however multiple lines have been a royal pain. This is kinda how I've been doing it:
"if-endif":{
"patterns": [
{
"begin":"(?im)(?<ifthen>(^\\s*if\\s+(\\w+|\\s+|=)+\\s+then$))(?=(g<ifthen>).*^\\s*endif$)*.*^\\s*endif$)",
"beginCaptures":{"1":{"name":"keyword.control.ifthen.ttl"}},
"end":"(?i)(?<=(ditto above lookahead)*)(^\\s*endif$))",
"endCaptures":{"1":{"name":"keyword.control.endif.ttl"}}
"patterns":[{"include":"#if-endif"},{"include":"#alltheotherthings"}]
}
]
}
Somehow I need to get the if/then and its matching endif while not accidently grabbing an endif that belongs do a different if. My biggest issue is I really have no idea how to deal with multiple lines in a regex apart from including (?m).
My other problem I'm not sure is even possible within the syntax. I'd like a way to see if a variable has already been defined in the above script so I can markup appropriately if I'm trying to use a string/integer in the wrong place, or if it hasn't been defined. However I'm not aware of any way to compare one capture group to another inside a regex. If anyone knows of a good example or documentation I'd be overjoyed. My primary docs I've been using for this are MS's vscode stuff and macromates.
Any pointers/help/links would be greatly appreciated. This is pretty much the last regex holding me up as everything else are single line affairs.
I have written a programme which merges two 1D arrays containing names. I print the list of arr1, arr2 and arr3.
I am using Lazarus Free Pascal v. 1.0.14 . I was wondering if anyone knows how to break the results in the dos-like window because the list is so long that I can only see the last few names in the returned results. The rest go by too fast to read.
I know I can save the resuls to file and I also use the delay command, but would like to know if there is a way to somehow break the results or slow them down or even edit the output console?
I appreciate your help.
This isn't really a programming question, because your console application should output the values without pause. Otherwise your program would become useless if you ever wanted it to run as part of another pipeline in an automated fashion.
Instead you need a tool that you wrap around your program to paginate the output if, and when, you so desire. Such tools are known as terminal pagers and the basic one that ships with Windows is called more. You execute your program and pipe the output to the more program. Like this:
C:\SomeDir>MyProject.exe <input_args> | more
You can change the code of your loop in the following way:
say you print the results by the followng loop:
for i:=0 to 250 do
WriteLn(ArrUnited[i]);
you can replace it with:
for i:=0 to 250 do
begin
WriteLn(ArrUnited[i]);
if (i mod 25) = 24 then //the code will wait for the user pressing Enter every 25 rows
ReadLn;
end;
For the future please! post MCVE in your questions otherwise everyone has to guess what your code is.
I'm trying to get my Jira data via JSON REST API into Excel, i.e. using VBA, and I'm parsing JSON output using RegEx. There are plenty of useful tutorials on the web, and after a couple of days I do have more or less working solution I'm happy with, except one minor obstacle. Long story short:
Among many issue fields I need friendly Assignee name, but some issues in my projects may be Unassigned, that obviously results in TWO VERY different kinds of JSON output:
Unassigned issue:
..."assignee":null,"updated"...
Assigned issue:
"assignee":{
"self":...
<Lots of NOT needed fields here>
...
},
"displayName":"Doe, John", <-- That's what I need, name only part
"active":...
<Lots of NOT needed fields here>
...
},
"updated"...
Well, I suppose that something like:
"assignee".*?"displayName":"(.*?)"|"assignee":(.*?),"updated"
will handle the job by producing TWO possible Matches, but... Is there a way to create RegEx where ANY of output options will result in SubMatches of ONE Match?
I'm a total newbie to RegEx, so sorry if the wording of my question is silly due to incorrectly used terms. Anyway, I hope the sample part is more or less clear, and I'll be extremely grateful for useful suggestions.
After an hour of tryouts on regex101 I ended up with the following RegEx:
"assignee":(null|.*?"displayName":"(.*?)","active")
Probably it's ugly and may be improved - but it DOES the job, and does NOT ruin in the process the indexes of subsequent Matches in collection, therefore keeping the rest of code working as it is now.
So I'm creating a vim script that needs to load and parse a JSON file into a local object graph. I searched and I couldn't find any native way to process a JSON file, and I don't want to add any dependencies to the script. So I wrote my own function to parse the JSON string (gotten from the file), but it's really slow. At the moment, I iterate through each character in the file like so:
let len = strlen(jsonString) - 1
let i = 0
while i < len
let c = strpart(jsonString, i, 1)
let i += 1
" A lot of code to process file....
" Note: I've tried short cutting the process by searching for enclosing double-quotes when I come across the initial double quotes (also taking into account escaping '\' character. It doesn't help
endwhile
I've also tried this method:
for c in split(jsonString, '\zs')
" Do a lot of parsing ....
endfor
For reference, a file with ~29,000 characters takes about 4 seconds to process, which is unacceptable.
Is there a better way to iterate over a string in vim script?
Or better yet, have I missed a native function to parse JSON?
Update:
I asked for no dependencies because I:
Didn't want to deal with them
Genuinely wanted some ideas for best way to do this without someone else's work.
Sometimes I just like to do things manually even though the problem has already been solved.
I'm not against plugins or dependencies at all, it's just that I'm curious. Thus the question.
I ended up creating my own function to parse the JSON file. I was creating a script that could parse the package.json file associated with node.js modules. Because of this, I could rely on a fairly consistent format and quit the processing whenever I'd retrieved the information I needed. This usually cut out large chunks of the file since most developers put the largest chunk of the file, their "readme" section, at the end. Because the package.json file is strictly defined, I left the process somewhat fragile. It assumed a root dictionary { } and actively looks for certain entries. You can find the script here: https://github.com/ahayman/vim-nodejs-complete/blob/master/after/ftplugin/javascript.vim#L33.
Of course, this doesn't answer my own question. It's only the solution to my unique problem. I'll wait a few days for new answers and pick the best one before the bounty ends (already set an alarm on my phone).
The simplest solution with the least dependencies is just using the json_decode vim function.
let dict = json_decode(jsonString)
Even though Vim's origin dates back a lot it happens that its internal string() eval() representation is that close to JSON that its likely to work unless you need special characters.
You can lookup the implementation here which even supports true/false/null if you want:
https://github.com/MarcWeber/vim-addon-json-encoding
Better use that library (vim-addon-manager allows to install dependencies easily).
Now it depends on your data whether this is good enough.
Now Benjamin Klein posted your question to vim_use which is why I'm replying.
Best and fast replies happen if you subscribe to the Vim mailinglist.
Goto vim.sf.net and follow the community link.
You cannot expect the Vim community to scrape stackoverflow.
I've added the keyword "json" and "parsing" to that little code that it can be found easier.
If this solution does not work for you you can try the many :h if_* bindings or write an external script which extracts the information you're looking for, or turns JSON into Vim's dictionary representation which can be read by eval() escaping special characters you care about correctly.
If you seek for completely correct solution omitting dependencies is one of the worst thing you can do. The eval() variant mentioned by #MarcWeber is one of the fastest, but it has its disadvantages:
Using solution for securing eval I mentioned in comment makes it no longer the fastest. In fact after you use this it makes eval() slower by more then an order of magnitude (0.02s vs 0.53s in my test).
It does not respect surrogate pairs.
It cannot be used to verify that you have correct JSON: it accepts some strings (e.g. "\<C-o>") that are not JSON strings and it allows trailing commas.
It fails to give normal error messages. It fails badly if you use vam#VerifyIsJSON I mentioned in p.1.
It fails to load floating point values like 1e10 (vim requires numbers to look like 1.0e10, but numbers like 1e10 are allowed: note “and/or” in the first paragraph).
. All of the above (except for the first) statements also apply to vim-addon-json-encoding mentioned by #MarcWeber because it uses eval. There are some other possibilities:
Fastest and the most correct is using python: pyeval('json.loads(vim.eval("varname"))'). Not faster then eval, but fastest among other possibilities. (0.04 in my test: approximately two times slower then eval())
Note that I use pyeval() here. If you want solution for vim version that lacks this functionality it will no longer be one of the fastest.
Use my json.vim plugin. It has an advantages of slightly better error reporting compared to failed vam#VerifyIsJSON, slightly worse compared to eval() and it correctly loads floating-point numbers. It can be used for verification of strings (it does not accept "\<C-a>"), but it loads lists with trailing comma just fine. It does not support surrogate pairs. It is also very slow: in the test I used (it uses 279702 character long strings) it takes 11.59s to load. Json.vim tries to use python if possible though.
For the best error reporting you can take yaml.vim and purge YAML support out of it leaving only JSON (I once have done the same thing for pyyaml, though in python: see markedjson library used in powerline: it is pyyaml minus YAML stuff plus classes with marks). But this variant is even slower then json.vim and should only be used if the main thing you need is error reporting: 207 seconds for loading the same 279702 character long string.
Note that the only variant mentioned that satisfies both requirements “no dependencies” and “no python” is eval(). If you are not fine with its disadvantages you have to throw away one or both of these requirements. Or copy-paste code. Though if you take speed into account only two candidates are left: eval() and python: if you want to parse json fast you really must use C and only these solutions spend most time in functions written in C.
Most other interpreters (ruby/perl/TCL) do not have pyeval() equivalent so they will be slower even if their JSON implementation is written in C. Some other (lua/racket (mzscheme)) have pyeval() equivalent, but e.g. luaeval('{}') is zero meaning that you will have to add additional step explicitly and recursively converting objects into vim dictionaries and lists (e.g. luaeval('vim.dict({})')) which will impact performance. Cannot say anything about mzeval(), but I have never heard about anybody actually using racket (mzscheme) with vim.
I want to be able to parse specific content from a website into a mySQL database. For example, on site http://allrecipes.com/Recipe/Fluffy-Pancakes-2/Detail.aspx I want to parse into my database (which has a table with columns RecipeName, Ingredients 1-10).
So basically my database will contain the name and all the ingredients for that recipe. There is no need to edit the content, simply parse them in as is (i.e. 3/4 cup milk) since i am using character in my database.
How exactly do I go about doing this? I was looking a pre-built parsers and it seems its tough to find one that's easy to use since I am fairly new to programming. Of course, I can manually enter values in but I want to parse them in.
Would it be possible to just parse this content and write a file that has a RecipieName, Ingredient string which I can then parse into my database? Or should I just do it directly into the database? I am unsure as to how to connect a database to a parser also directly, but I might be able to find some information online.
Basically, I am looking for help on how to exactly go about doing this since I am not very well versed in programming and this seems to be a lot more complicated than it might be.
I am using Java as my main language right now, although I can't say I am very good at it. But I should be able to understand the basic concepts.
Any suggestions on what parser to use or how to do this?
Thanks!
This is how I would do it in PHP. This is almost certainly NOT the most efficient way to do it, nor has it been debugged.
function parseHTML($rawHTML){
$startPosition = strpos($rawHTML,'<div class="ingredients"'); //Find the position of the beginning of the ingredients list, return the character number.
$endPosition = strpos($rawHTML,'</div>',$startPosition); //Find the position of the end of the ingredients list, begin searching from the beginning of the list (found in step 1)
$relevantPart = substr($rawHTML,$startPosition,$endPosition); //Isolate the ingredients list
$parsedString = strip_tags($relevantPart); //Strip the HTML tags off of the ingredients list
return $parsedString;
}
Still to be done: You say you have a mySQL database with 10 separate ingredients columns. This code outputs everything as one big string. You would have to change the strip_tags($relevantPart) function to strip_tags($relevantPart,"<li>"). That would let the <li> tags through. Then, you would have to loop through every <li> tag, performing a similar function to this. It shouldn't be too hard, but I don't feel comfortable writing it with no functioning PHP server.