Re: reading (parsing) CSV (or Excel) data
On Thu, Oct 1, 2009 at 7:09 PM, Colin Howarth wrote:
> Hi,
>
> I'd like my app ('tis progressing steadily :-) to read some simple tabular
> data. The original file is from Excel, but it's not too much bother to
> convert it to CSV.
>
> Searching the developer docs gets me
>
> "gestaltGraphicsVersion"
>
> which is not good, but googling "cocoa csv" works very well. The first
> couple of thousand hits seem relevant :-)
>
> Before I go through the 550,000 hits (some of them quite old) dare I ask if
> there's one Right Way (TM) to parse this sort of data?
>
One possible solution I haven't seen mentioned yet is to use RegexKitLite (
http://downloads.sourceforge.net/regexkit/RegexKitLite-3.1.tar.bz2). The
documentation has an example that parses CSV strings (
http://regexkit.sourceforge.net/RegexKitLite/index.html#RegexKitLiteCookbook_PatternMatchingRecipes_TextFiles_ParsingCSVData).
When I did some simple benchmarks parsing CSV files using the
documentations example code, it significantly outperformed other solutions
that I tried. One of those was the MacResearch example that's already been
mentioned, but this was some time ago, so things may have changed and your
milage may vary. It only takes ~17 lines of code to parse CSV strings in to
a NSArray (lines) of NSArrays ('columns') using RegexKitLite, so making
modifications to fit your particular needs is very doable.
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Re: reading (parsing) CSV (or Excel) data
On Oct 2, 2009, at 4:19 PM, Alex Kac wrote: Yes! In any case, I'm sure libcsv is more powerful and correct, but the category there worked for my purposes working with several cloud services. You need only address quoted fields, line breaks within fields, respect character encodings, and line ending variations (CR/LF/CR+LF). Cocoa handles two of these four automagically (in most cases for character encodings, all cases for line endings). The parsing category on macresearch.org adds the other two. I'm fascinated by the NSMutableCharacterSet efficiency issue but the category seems to work quickly on impressively-sized files (100,000 records with 100 fields, with reasonably long text in the fields), despite its memory inefficiencies. I'll be giving it a test with Mike's suggested modification to see how much better it runs, though. :-) -- I.S. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
Yes! In any case, I'm sure libcsv is more powerful and correct, but the category there worked for my purposes working with several cloud services. On Oct 2, 2009, at 3:16 PM, I. Savant wrote: On Oct 2, 2009, at 4:15 PM, Alex Kac wrote: Here is something I use that has worked for me fairly well. I found it either on this list or somewhere on the web, so sharing back to the list. http://pastie.org/639863 This appears to be the code listing from the article I mentioned on MacResearch.org . :-) -- I.S. Alex Kac - President and Founder Web Information Solutions, Inc. "It is useless for sheep to pass a resolution in favor of vegetarianism while wolves remain of a different opinion." -- William Randolph Inge ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
On Oct 2, 2009, at 4:15 PM, Alex Kac wrote: Here is something I use that has worked for me fairly well. I found it either on this list or somewhere on the web, so sharing back to the list. http://pastie.org/639863 This appears to be the code listing from the article I mentioned on MacResearch.org . :-) -- I.S. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
On Oct 2, 2009, at 4:03 PM, Colin Howarth wrote: CSV isn't *that* hard to parse, once you know about quotes and NLs inside cells. ... and encodings and line endings. Don't forget how much goodness Cocoa gives you automagically. :-) -- I.S. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
Here is something I use that has worked for me fairly well. I found it either on this list or somewhere on the web, so sharing back to the list. http://pastie.org/639863 On Oct 2, 2009, at 3:03 PM, Colin Howarth wrote: Yes, thanks Mike (and all others). My particular table is only around 100 x 100 cells, so Drew's code is fine. Regarding the efficiency points raised in these posts, perhaps Stephen's pointer libcsv is a potential option. http://sourceforge.net/projects/libcsv/ is a good idea. CSV isn't *that* hard to parse, once you know about quotes and NLs inside cells. Maybe a Cocoa wrapper enabling one to *use* libcsv in a Cocoa-ish way would be a good idea. You don't really need to create an instance with [MyLetter letterWithLetter: (chr) aLetter encodedUsingEncoding: (NSStringEncoding *) someEncoding possiblyUsingSomeFont: (NSFont *) aFont] or [MyLetter createALetterByReadingFromString:(NSString *) theStringImLookingAt whichMightBeEncodedUsingEncoding:(NSEncoding *) anEncoding butIfItIsntEncodedOrIfICantFigureOutTheEncodingLookAtThisError: (NSError ***) error andAssignANiceFont: (NSFont *)font andOfCourseASize: (NSPointSize *) makeAPointSizeNumberUsingANumber ( pointSize)] for each letter in the file and then [parser lookAtTheLetterIJustRead: (MyLetter *) theLetter andDecideIfItBelongsToTheMutableClassOfSeparatorCharacters: (NSMutableArray *) ... ... :-) (sorry) I mean, one doesn't *have to* implement the parser in Objective-C, does one? Maybe I'll have a go (I need the practice) when I've Finished (TM) my current project... -- colin On 2 Oct, 2009, at 15:49, Adam R. Maxwell wrote: On Oct 2, 2009, at 6:10 AM, I. Savant wrote: On Oct 2, 2009, at 7:42 AM, Mike Abdullah wrote: While using this code in an experimental project I found the app was routinely using 500+ MB of RAM. When measured with Instruments I realised that every time you use a character set for string scanning, Foundation internally copies it, presumably to ensure it has an immutable object to work with. As a result, potentially thousands of copies are being created, resulting in either: A) Outrunning the garbage collector B) Spending far more time allocating and deallocating character sets than doing the actual scanning Easiest solution is just to make a single copy yourself early on. Also the docs for NSMutableCharacterSet do point out that it's inefficient but don't really offer any detail. Very good to know, thanks, Mike. You might want to post a comment on the macresearch.org page so Drew can adjust the example. I've also run into major performance problems with -[NSScanner scanCharactersFromSet:], which creates an inverted, autoreleased character set each time it's called. This blows up autorelease pools (and inverting character sets isn't fast either). Filed as rdar://problem/4652388. My workaround for this is generally to invert the set myself and use scanUpToCharactersFromSet:, but that could be hurting this example as well. Do you happen to remember what percentage of difference you were able to achieve? It's fine if not - it's not too difficult to set up a test. :-) In my case I was running out of address space and crashing, which is pretty easy to detect :). ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/colin%40howarth.de This email sent to co...@howarth.de ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/alex%40webis.net This email sent to a...@webis.net Alex Kac - President and Founder Web Information Solutions, Inc. "You cannot build a reputation on what you intend to do." -- Liz Smith ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
Yes, thanks Mike (and all others). My particular table is only around 100 x 100 cells, so Drew's code is fine. Regarding the efficiency points raised in these posts, perhaps Stephen's pointer libcsv is a potential option. http://sourceforge.net/projects/ libcsv/ is a good idea. CSV isn't *that* hard to parse, once you know about quotes and NLs inside cells. Maybe a Cocoa wrapper enabling one to *use* libcsv in a Cocoa-ish way would be a good idea. You don't really need to create an instance with [MyLetter letterWithLetter: (chr) aLetter encodedUsingEncoding: (NSStringEncoding *) someEncoding possiblyUsingSomeFont: (NSFont *) aFont] or [MyLetter createALetterByReadingFromString:(NSString *) theStringImLookingAt whichMightBeEncodedUsingEncoding:(NSEncoding *) anEncoding butIfItIsntEncodedOrIfICantFigureOutTheEncodingLookAtThisError: (NSError ***) error andAssignANiceFont: (NSFont *)font andOfCourseASize: (NSPointSize *) makeAPointSizeNumberUsingANumber ( pointSize)] for each letter in the file and then [parser lookAtTheLetterIJustRead: (MyLetter *) theLetter andDecideIfItBelongsToTheMutableClassOfSeparatorCharacters: (NSMutableArray *) ... ... :-) (sorry) I mean, one doesn't *have to* implement the parser in Objective-C, does one? Maybe I'll have a go (I need the practice) when I've Finished (TM) my current project... -- colin On 2 Oct, 2009, at 15:49, Adam R. Maxwell wrote: On Oct 2, 2009, at 6:10 AM, I. Savant wrote: On Oct 2, 2009, at 7:42 AM, Mike Abdullah wrote: While using this code in an experimental project I found the app was routinely using 500+ MB of RAM. When measured with Instruments I realised that every time you use a character set for string scanning, Foundation internally copies it, presumably to ensure it has an immutable object to work with. As a result, potentially thousands of copies are being created, resulting in either: A) Outrunning the garbage collector B) Spending far more time allocating and deallocating character sets than doing the actual scanning Easiest solution is just to make a single copy yourself early on. Also the docs for NSMutableCharacterSet do point out that it's inefficient but don't really offer any detail. Very good to know, thanks, Mike. You might want to post a comment on the macresearch.org page so Drew can adjust the example. I've also run into major performance problems with -[NSScanner scanCharactersFromSet:], which creates an inverted, autoreleased character set each time it's called. This blows up autorelease pools (and inverting character sets isn't fast either). Filed as rdar://problem/4652388. My workaround for this is generally to invert the set myself and use scanUpToCharactersFromSet:, but that could be hurting this example as well. Do you happen to remember what percentage of difference you were able to achieve? It's fine if not - it's not too difficult to set up a test. :-) In my case I was running out of address space and crashing, which is pretty easy to detect :). ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/colin%40howarth.de This email sent to co...@howarth.de ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
On Fri, Oct 2, 2009 at 11:27 AM, DKJ wrote: > I've just been using NSXMLParser for the first time. Can Excel files be > saved in XML format? If so, would NSXMLParser be a possible solution here? XML isn't a format, per se. It's a structured markup language. The actual layout of the data (the schema) is undefined. I might do this: 123 While someone else might do this: 123 Both of these are XML, but in completely different schemata. So "XML format" is a bit nonsensical. The native file format of Excel 2007 and 2008 is indeed an XML-based format, and it's even a standard. It's also so terribly complex that there is as of yet no 100%-compliant editor of this format. --Kyle Sluder ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
I've just been using NSXMLParser for the first time. Can Excel files be saved in XML format? If so, would NSXMLParser be a possible solution here? dkj ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
On Oct 2, 2009, at 6:10 AM, I. Savant wrote: On Oct 2, 2009, at 7:42 AM, Mike Abdullah wrote: While using this code in an experimental project I found the app was routinely using 500+ MB of RAM. When measured with Instruments I realised that every time you use a character set for string scanning, Foundation internally copies it, presumably to ensure it has an immutable object to work with. As a result, potentially thousands of copies are being created, resulting in either: A) Outrunning the garbage collector B) Spending far more time allocating and deallocating character sets than doing the actual scanning Easiest solution is just to make a single copy yourself early on. Also the docs for NSMutableCharacterSet do point out that it's inefficient but don't really offer any detail. Very good to know, thanks, Mike. You might want to post a comment on the macresearch.org page so Drew can adjust the example. I've also run into major performance problems with -[NSScanner scanCharactersFromSet:], which creates an inverted, autoreleased character set each time it's called. This blows up autorelease pools (and inverting character sets isn't fast either). Filed as rdar://problem/4652388. My workaround for this is generally to invert the set myself and use scanUpToCharactersFromSet:, but that could be hurting this example as well. Do you happen to remember what percentage of difference you were able to achieve? It's fine if not - it's not too difficult to set up a test. :-) In my case I was running out of address space and crashing, which is pretty easy to detect :). smime.p7s Description: S/MIME cryptographic signature ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
On Oct 2, 2009, at 7:42 AM, Mike Abdullah wrote: While using this code in an experimental project I found the app was routinely using 500+ MB of RAM. When measured with Instruments I realised that every time you use a character set for string scanning, Foundation internally copies it, presumably to ensure it has an immutable object to work with. As a result, potentially thousands of copies are being created, resulting in either: A) Outrunning the garbage collector B) Spending far more time allocating and deallocating character sets than doing the actual scanning Easiest solution is just to make a single copy yourself early on. Also the docs for NSMutableCharacterSet do point out that it's inefficient but don't really offer any detail. Very good to know, thanks, Mike. You might want to post a comment on the macresearch.org page so Drew can adjust the example. Do you happen to remember what percentage of difference you were able to achieve? It's fine if not - it's not too difficult to set up a test. :-) -- I.S. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Re: reading (parsing) CSV (or Excel) data
Before I go through the 550,000 hits (some of them quite old) dare I ask if there's one Right Way (TM) to parse this sort of data? I'm not aware of one Right Way (™) here. If you're stuck due to somebody else's decision to use CSV, libcsv is a potential option. http://sourceforge.net/projects/libcsv/ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
While using this code in an experimental project I found the app was routinely using 500+ MB of RAM. When measured with Instruments I realised that every time you use a character set for string scanning, Foundation internally copies it, presumably to ensure it has an immutable object to work with. As a result, potentially thousands of copies are being created, resulting in either: A) Outrunning the garbage collector B) Spending far more time allocating and deallocating character sets than doing the actual scanning Easiest solution is just to make a single copy yourself early on. Also the docs for NSMutableCharacterSet do point out that it's inefficient but don't really offer any detail. Mike. On 2 Oct 2009, at 12:02, I. Savant wrote: On Oct 2, 2009, at 6:34 AM, Mike Abdullah wrote: inefficient due to its use of NSMutableCharacterSet. Could you expand on this? Once created and manipulated, what makes it slow for string scanning compared to NSCharacterSet? I hadn't heard this. -- I.S. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
On Oct 2, 2009, at 6:34 AM, Mike Abdullah wrote: inefficient due to its use of NSMutableCharacterSet. Could you expand on this? Once created and manipulated, what makes it slow for string scanning compared to NSCharacterSet? I hadn't heard this. -- I.S. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
On 2 Oct 2009, at 02:37, Colin Howarth wrote: Thanks everyone! The idiot savant was first to point out the http://macresearch.org/cocoa-scientists-part-xxvi-parsing-csv-data link. And that one refers also to the cocoadev site. As a warning, that particular bit of code is pretty inefficient due to its use of NSMutableCharacterSet. You will find that with any large- ish data set it starts allocating vast quantities of memory. But not to worry, it's dead easy to fix; just make sure you -copy to create an NSCharacterSet before scanning and it will be more efficient. Mike. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
Thanks everyone! The idiot savant was first to point out the http://macresearch.org/cocoa-scientists-part-xxvi-parsing-csv-data link. And that one refers also to the cocoadev site. It seems everyone expects there to be a standard Cocoa solution, is surprised that there isn't, and develops their own, or goes stumbling around the web to see what others have come up with. :-) --colin On 2 Oct, 2009, at 03:13, Greg Guerin wrote: http://www.cocoadev.com/index.pl?ReadWriteCSVAndTSV That site has enough good stuff, often with links to other stuff, that it's worth using a site:cocoadev.com qualifier in your googling. Or just start there. -- GG ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/colin%40howarth.de This email sent to co...@howarth.de ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
http://www.cocoadev.com/index.pl?ReadWriteCSVAndTSV That site has enough good stuff, often with links to other stuff, that it's worth using a site:cocoadev.com qualifier in your googling. Or just start there. -- GG ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
On Oct 1, 2009, at 5:22 PM, Jens Alfke wrote: On Oct 1, 2009, at 4:09 PM, Colin Howarth wrote: Before I go through the 550,000 hits (some of them quite old) dare I ask if there's one Right Way (TM) to parse this sort of data? If the data's not too huge, you can read the file into an NSString, break that into lines (there are some NSString methods for this, but I don't remember their names), and then on each line call [line componentsSeparatedByString: @","] to get the values in an NSArray. The values will be strings not numbers, but you can call -intValue or -doubleValue on each one to convert it. As has been pointed out, .csv files are not quite that simple. The .csv format is actually an official RFC (RFC-4180). .csv is not very difficult to parse, but there are some subtleties around the quoting and newlines: http://www.rfc-editor.org/rfc/rfc4180.txt I don't know whether Excel strictly adheres to the RFC, but a .csv parser that I wrote a number of years ago that follows the RFC has so far been quite successful parsing Excel-generated .csvs without complaint. -- Rick Genter rick.gen...@gmail.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
On 02/10/2009, at 10:22 AM, Jens Alfke wrote: If the data's not too huge, you can read the file into an NSString, break that into lines (there are some NSString methods for this, but I don't remember their names), and then on each line call [line componentsSeparatedByString: @","] to get the values in an NSArray. That won't work. CSV can contain commas and newlines within items if encapsulated in quotes. The values will be strings not numbers, but you can call -intValue or -doubleValue on each one to convert it. Yes, CSV doesn't specify types, just strings, so any interpretation you make on types is after the actual CSV import. I found this method (the one under the heading "General CSV"), which works fine, caters for delimiters within quotes, escaped quotes etc: http://macresearch.org/cocoa-scientists-part-xxvi-parsing-csv-data Tom BareFeet ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: reading (parsing) CSV (or Excel) data
On Oct 1, 2009, at 4:09 PM, Colin Howarth wrote: Before I go through the 550,000 hits (some of them quite old) dare I ask if there's one Right Way (TM) to parse this sort of data? If the data's not too huge, you can read the file into an NSString, break that into lines (there are some NSString methods for this, but I don't remember their names), and then on each line call [line componentsSeparatedByString: @","] to get the values in an NSArray. The values will be strings not numbers, but you can call -intValue or - doubleValue on each one to convert it. If you have huge amounts of data, like hundreds of thousands of lines, this is going to become noticeably inefficient, so you might need to start reading and parsing directly from the file. —Jens___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
reading (parsing) CSV (or Excel) data
Hi,
I'd like my app ('tis progressing steadily :-) to read some simple
tabular data. The original file is from Excel, but it's not too much
bother to convert it to CSV.
Searching the developer docs gets me
"gestaltGraphicsVersion"
which is not good, but googling "cocoa csv" works very well. The first
couple of thousand hits seem relevant :-)
Before I go through the 550,000 hits (some of them quite old) dare I
ask if there's one Right Way (TM) to parse this sort of data?
Thanks,
--colin
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