In my app (for iPad) I want to use a large quanitity of data. It function in this way: if I select an argument in a row of a tableview I must show much text. The solution that I think to use for this app is a big file xml or more file xml to contain tis data. Is a correct way? or is there a best way to contain this data quantity of string? Where can I store this amount of data?
You could take a look to Proxy Design pattern.
http://en.wikipedia.org/wiki/Proxy_pattern
Actually small xml, and big xml should work but make care that your code design is good.
Related
[![enter image description here][4]][4][![enter image description here][5]][5]I have a PDF that has tabular data that runs over 50+ pages, i want to extract this table into an excel file using Automation Anywhere. (i am using community version of AA 11.3). I watched videos of the PDF integration command but haven't had any success trying this for tabular data.
Requesting assistance.
Thanks.
I am afraid that your case will be quite challenging... and the main reason for that are the values that contains multiple lines. You can still achieve what you need, and with good performance, but the code itself will not be pretty. You will also be facing challanges with Automation Anywhere, since it does not really provide the right tools to do such a thing and you may need to resort to scripting (VBScripts) or Metabots.
Solution 1
This one will try to use purely text extraction and Regular expressions. Mainly standard functionality, nothing too "dirty".
First you need to realise how do the exported data look like. You can see that you can export to Plain or Structured.
The Plain one is not useful at all as the data is all over the place, without any clear pattern.
The Structured one is much better as the data structure resembles the data from the original document. From looking at the data you can make these observations:
Each row contains 5 columns
All columns are always filled (at least in the visible sample set)
The last two columns can serve as a pattern "anchor" (identifier), because they contain a clear pattern (a number followed by minimum of two spaces followed by a dollar sign and another number)
Rows with data are separated by a blank row
The text columns may contain a multiline value, which will duplicate the rows (this one thing makes it especially tricky)
First wou need to ensure that the Structured data contain only the table, nothing else. You can probably use the Before-After string command for that.
Then you need to check if you can reliably identify the character width of every column. You can try this for yourself if you copy the text into Excel, use the Text to Columns with the Fixed Width option and try to play around with the sliders
The you need to try to find a way how to reliably identify each row and prepare it for the Split command in AA. For that you need to have a delimiter. But since each data row can actually consists of multiple text rows, you need to create a delimiter of your own. I used the Replace function with Regular Expression option and replace a specific pattern for a delimiter (pipe). See here.
Now that you have added a custom delimiter, you can use the Split command to add each row into a list and loop through it.
Because each data row may consists of several rows, you will need to use Split again, this time use the [ENTER] as delimiter. Now you need to loop through each of the text line of a single data line and use the Substring function to extract data based on column width and concatenate them to a single value that you store somewhere else.
All in all, a painful process.
Solution 2
This may not be applicable, but it's worth a try - open the PDF in Microsoft Word. It will give you a warning, ignore it. Word will attempt to open the document and, if you're lucky, it will recognise your table as a table. If it works, it will make the data extraction much easier an you will be able to use Macros/VBA or even simple Copy&Paste. I tried it on a random PDF of my own and it works quite well.
I'm using the same zachrone iphonepdf but I did not get the text. My text view shows nothing. What's the problem?
Here is my code:
NSString *text=convertPDF(#"Course.pdf");
texview.text=text;
But I did not get anything in text view?
The text extractor zachron / pdfiphone (I assume you meant that one) is extremely naive and makes very many assumptions.
It ignores the PDF file structure and, therefore completely ignores whether the data it inspects is still used in the current revision.
It ignores encryption and therefore will fail completely for many documents with usage restrictions.
It completely ignores font encodings and implicitely assumes an ASCII'ish one --- this is fairly often true in small PDFs with English text only and not embedded fonts; otherwise the result can be anything.
... many many more assumptions ...
Unless one only has to deal with very simple documents and the extracted text is not really necessary for the functionality of one's code, I would propose using different code for text extraction.
I am looking to create a navigation based reference app for the iOS.
I have considered the following ways to store the data:
hard coding
plist file
some kind of comma delimited file
The data structure that I will be using has a bunch of strings, an array, and a reference to a picture.
What do you think the best way to store this data is without getting into CoreData?
Thanks
Also I dont think it would be more than 500 entries.
Well, this is not a "best-practice" problem for any case.
The data structure that I will be using has a bunch of strings, an array, and a reference to a picture.
What do you think the best way to store this data is without getting into CoreData?
For your needs, I suggest you look into NSKeyedArchiver.
NSString, NSArray, and UIImage all know how to encode and decode themselves. Just use an NSKeyedArchiver. Note that the objects in your collections (e.g. NSArray) must adopt #protocol NSCoding.
If you need to open this on a mac, then convert the UIImage to NSData using a proper image file format representation (e.g. PNG or JPEG) because UIImage is not available.
In detail:
hard coding
That could mean a number of things.
plist file
You're working with large non-plist types. That would mean you would need to convert to and from UIImage<->NSData unnecessarily, which would add a lot of overhead -- memory, CPU, and potentially file size. All these types can encode themselves better than (or as good as) a plist representation.
some kind of comma delimited file
Your image will not allow that to happen (reliably).
I have an application for storing many strings in a TStringList. The strings will be largely similar to one another and it occurs to me that one could compress them on the fly - i.e. store a given string in terms of a mixture of unique text fragments plus references to previously stored fragments. StringLists such as lists of fully-qualified path and filenames should be able to be compressed greatly.
Does anyone know of a TStringlist descendant that implement this - i.e. provides read and write access to the uncompressed strings but stores them internally compressed, so that a TStringList.SaveToFile produces a compressed file?
While you could implement this by uncompressing the entire stringlist before each access and re-compressing it afterwards, it would be unnecessarily slow. I'm after something that is efficient for incremental operations and random "seeks" and reads.
TIA
Ross
I don't think there's any freely available implementation around for this (not that I know of anyway, although I've written at least 3 similar constructs in commercial code), so you'd have to roll your own.
The remark Marcelo made about adding items in order is very relevant, as I suppose you'll probably want to compress the data at addition time - having quick access to entries already similar to the one being added, gives a much better performance than having to look up a 'best fit entry' (needed for similarity-compression) over the entire set.
Another thing you might want to read up about, are 'ropes' - a conceptually different type than strings, which I already suggested to Marco Cantu a while back. At the cost of a next-pointer per 'twine' (for lack of a better word) you can concatenate parts of a string without keeping any duplicate data around. The main problem is how to retrieve the parts that can be combined into a new 'rope', representing your original string. Once that problem is solved, you can reconstruct the data as a string at any time, while still having compact storage.
If you don't want to go the 'rope' route, you could also try something called 'prefix reduction', which is a simple form of compression - just start out each string with an index of a previous string and the number of characters that should be treated as a prefix for the new string. Be aware that you should not recurse this too far back, or access-speed will suffer greatly. In one simple implementation, I did a mod 16 on the index, to establish the entry at which prefix-reduction started, which gave me on average about 40% memory savings (this number is completely data-dependant of course).
You could try to wrap a Delphi or COM API around Judy arrays. The JudySL type would do the trick, and has a fairly simple interface.
EDIT: I assume you are storing unique strings and want to (or are happy to) store them in lexicographical order. If these constraints aren't acceptable, then Judy arrays are not for you. Mind you, any compression system will suffer if you don't sort your strings.
I suppose you expect general flexibility from the list (including delete operation), in this case I don't know about any out of the box solution, but I'd suggest one of the two approaches:
You split your string into words and
keep separated growning dictionary
to reference the words and save list of indexes internally
You implement something related to
zlib stream available in Delphi, but operating by the block that
for example can contains 10-100
strings. In this case you still have
to recompress/compress the complete
block, but the "price" you pay is lower.
I dont think you really want to compress TStrings items in memory, because it terribly ineffecient. I suggest you to look at TStream implementation in Zlib unit. Just wrap regular stream into TDecompressionStream on load and TCompressionStream on save (you can even emit gzip header there).
Hint: you will want to override LoadFromStream/SaveToStream instead of LoadFromFile/SaveToFile
In an experimental project I am playing with I want to be able to look at textual data and detect whether it contains data in a tabular format. Of course there are a lot of cases that could look like tabular data, so I was wondering what sort of algorithm I'd need to research to look for common features.
My first thought was to write a long switch/case statement that checked for data seperated by tabs, and then another case for data separated by pipe symbols and then yet another case for data separated in another way etc etc. Now of course I realize that I would have to come up with a list of different things to detect - but I wondered if there was a more intelligent way of detecting these features than doing a relatively slow search for each type.
I realize this question isn't especially eloquently put so I hope it makes some sense!
Any ideas?
(no idea how to tag this either - so help there is welcomed!)
The only reliable scheme would be to use machine-learning. You could, for example, train a perceptron classifier on a stack of examples of tabular and non-tabular materials.
A mixed solution might be appropriate, i.e. one whereby you handled the most common/obvious cases with simple heuristics (handled in "switch-like" manner) as you suggested, and to leave the harder cases, for automated-learning and other types of classifier-logic.
This assumes that you do not already have a defined types stored in the TSV.
A TSV file is typically
[Value1]\t[Value..N]\n
My suggestion would be to:
Count up all the tabs
Count up all of new lines
Count the total tabs in the first row
Divide the total number of tabs by the tabs in the first row
With the result of 4, if you get a remainder of 0 then you have a candidate of TSV files. From there you may either want to do the following things:
You can continue reading the data and ignoring the error of lines with less or more than the predicted tabs per line
You can scan each line before reading to make sure all are consistent
You can read up to the line that does not fit the format and then throw an error
Once you have a good prediction of the amount of tab separated values you can use a regular expression to parse out the values [as a group].