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c# : string[] to int[]
elegant method other than iterating through it and using int.parse() on each element? Thanks,
No.
[quoted text, click to view] "Andrew Robinson" <nemoby@nospam.nospam> wrote in message news:uqLHol4MGHA.1288@TK2MSFTNGP09.phx.gbl... >I have an array of string that I need to convert to an array of int. Any >elegant method other than iterating through it and using int.parse() on >each element? > > Thanks, >
Going to answer my own question here:
string[] input = { "1", "2", "3", "4", "5", "6", "7", "8", "9" }; int[] output = Array.ConvertAll<string, int>(input, delegate(string s) { return int.Parse(s); }); [quoted text, click to view] "Andrew Robinson" <nemoby@nospam.nospam> wrote in message news:uqLHol4MGHA.1288@TK2MSFTNGP09.phx.gbl... >I have an array of string that I need to convert to an array of int. Any >elegant method other than iterating through it and using int.parse() on >each element? > > Thanks, >
I guess it is when you get right down to it.
-A [quoted text, click to view] "Stephany Young" <noone@localhost> wrote in message news:O7QsJ34MGHA.2336@TK2MSFTNGP12.phx.gbl... > Did you read the part in the documentation for Array.ConvertAll where it > states: > > The elements of array are individually passed > to the Converter, and the converted elements > are saved in the new array. > > If that's not iteration then I don't know what is. > > > "Andrew Robinson" <nemoby@nospam.nospam> wrote in message > news:OfNYOy4MGHA.2528@TK2MSFTNGP12.phx.gbl... >> Going to answer my own question here: >> >> string[] input = { "1", "2", "3", "4", "5", "6", "7", "8", "9" }; >> >> int[] output = Array.ConvertAll<string, int>(input, delegate(string s) >> { return int.Parse(s); }); >> >> >> "Andrew Robinson" <nemoby@nospam.nospam> wrote in message >> news:uqLHol4MGHA.1288@TK2MSFTNGP09.phx.gbl... >>>I have an array of string that I need to convert to an array of int. Any >>>elegant method other than iterating through it and using int.parse() on >>>each element? >>> >>> Thanks, >>> >> >> > >
[quoted text, click to view]
>>Did you read the part in the documentation for Array.ConvertAll where it >>states: >> >> The elements of array are individually passed >> to the Converter, and the converted elements >> are saved in the new array. >> >>If that's not iteration then I don't know what is. Yes, but I think the value of this kind of thing is that the OP doesn't have to do the iterating himself. The mantra is "code reuse". The elegant part of ConvertAll is that it does what you want and you don't have to write any code. my 2 cents
Agreed. However, from my point of view, the important thing is control over
what is happening. Take a modified example of Andrew's example where one or more elements of the string array have values that will fail an int.Parse operation. All one gets is an exception with no information as to which element is at fault. One then would still have to iterate 'manually' through the array to determine which element or elements are invalid. If one converts the string array by iteration 'manually', then one has the opportunity to 'catch and report' any elements that will fail the conversion. Although there are a lot of what I call 'code savers' that are very useful, one has to be circumspect when using them so that one avoids unintended consequences. [quoted text, click to view] "Scott C" <sdcoonce@g_m_a_i_l.com> wrote in message news:OpoGwU5MGHA.3856@TK2MSFTNGP12.phx.gbl... >>>Did you read the part in the documentation for Array.ConvertAll where it >>>states: >>> >>> The elements of array are individually passed >>> to the Converter, and the converted elements >>> are saved in the new array. >>> >>>If that's not iteration then I don't know what is. > > Yes, but I think the value of this kind of thing is that the OP doesn't > have to do the iterating himself. The mantra is "code reuse". > > The elegant part of ConvertAll is that it does what you want and you don't > have to write any code. > > my 2 cents > > Scott
I'm not sure it's that different either way; in the anonymous delegate you
would still have access to e.g. any error collection etc that is scoped by the containing method, or any class members like events. Because of this, in a scenario like this the only thing that would make me choose one over the other is performance; I remember a chain a little while ago (here) comparing foreach, ForEach and indexer based access : embarrasingly I can't remember which one won ;-( Marc
[quoted text, click to view]
> I'm not sure it's that different either way; in the anonymous delegate > you would still have access to e.g. any error collection etc that is > scoped by the containing method, or any class members like events. > > Because of this, in a scenario like this the only thing that would > make me choose one over the other is performance; I remember a chain a > little while ago (here) comparing foreach, ForEach and indexer based > access : embarrasingly I can't remember which one won ;-( > > Marc > The article taking on ForEach, indexer, etc. is found here: http://msmvps.com/blogs/jon.skeet/archive/2006/01/20/foreachperf.aspx -- Lasse Vågsæther Karlsen http://usinglvkblog.blogspot.com/ mailto:lasse@vkarlsen.no PGP KeyID: 0x2A42A1C
Did you read the part in the documentation for Array.ConvertAll where it
states: The elements of array are individually passed to the Converter, and the converted elements are saved in the new array. If that's not iteration then I don't know what is. [quoted text, click to view] "Andrew Robinson" <nemoby@nospam.nospam> wrote in message news:OfNYOy4MGHA.2528@TK2MSFTNGP12.phx.gbl... > Going to answer my own question here: > > string[] input = { "1", "2", "3", "4", "5", "6", "7", "8", "9" }; > > int[] output = Array.ConvertAll<string, int>(input, delegate(string s) { > return int.Parse(s); }); > > > "Andrew Robinson" <nemoby@nospam.nospam> wrote in message > news:uqLHol4MGHA.1288@TK2MSFTNGP09.phx.gbl... >>I have an array of string that I need to convert to an array of int. Any >>elegant method other than iterating through it and using int.parse() on >>each element? >> >> Thanks, >> > >
[quoted text, click to view]
Marc Gravell wrote: > I'm not sure it's that different either way; in the anonymous delegate you > would still have access to e.g. any error collection etc that is scoped by > the containing method, or any class members like events. I was thinking about that - and there's *one* difference which springs to mind. If you use a plain for loop with an index, you get to know the *indexes* of which elements are invalid (or whatever). If you use foreach or the collection methods, you only get to know the *values*. Sometimes the indexes could be important (eg to highlight invalid rows in a UI). [quoted text, click to view] > Because of this, in a scenario like this the only thing that would make me > choose one over the other is performance; I remember a chain a little while > ago (here) comparing foreach, ForEach and indexer based access : > embarrasingly I can't remember which one won ;-( See http://msmvps.com/blogs/jon.skeet/archive/2006/01/20/foreachperf.aspx I would expect even the reasonably cheap operation of parsing integers to dwarf the iteration performance. Unless you have a good reason to believe that performance is particularly important in a given situation, it's one of the *last* reasons I would use to choose one over the other. I'd go for simplicity and readability primarily - and that will depend on what error handling is required etc. Jon
Thanks for all the info. Never thought I would spark such an interesting
discussion. In my case, I am using this to read values out of a config file. I prefer using a foreach over a for loop when ever I can. The following is in need of exception handling but given all that I have learned, I would choose this over a more "manual" approach. <appSettings> <add key="MachineIDs" value="44,3,43,566" /> </appSettings> private int[] GetConfigIntArray(string key) { string[] values = ConfigurationManager.AppSettings[key].Split(','); return Array.ConvertAll<string, int>(values, delegate(string s) { return int.Parse(s); }); } Thanks, -Andrew [quoted text, click to view] "Jon Skeet [C# MVP]" <skeet@pobox.com> wrote in message news:1140170997.629553.115900@g43g2000cwa.googlegroups.com... > Marc Gravell wrote: >> I'm not sure it's that different either way; in the anonymous delegate >> you >> would still have access to e.g. any error collection etc that is scoped >> by >> the containing method, or any class members like events. > > I was thinking about that - and there's *one* difference which springs > to mind. If you use a plain for loop with an index, you get to know the > *indexes* of which elements are invalid (or whatever). If you use > foreach or the collection methods, you only get to know the *values*. > Sometimes the indexes could be important (eg to highlight invalid rows > in a UI). > >> Because of this, in a scenario like this the only thing that would make >> me >> choose one over the other is performance; I remember a chain a little >> while >> ago (here) comparing foreach, ForEach and indexer based access : >> embarrasingly I can't remember which one won ;-( > > See > http://msmvps.com/blogs/jon.skeet/archive/2006/01/20/foreachperf.aspx > > I would expect even the reasonably cheap operation of parsing integers > to dwarf the iteration performance. > > Unless you have a good reason to believe that performance is > particularly important in a given situation, it's one of the *last* > reasons I would use to choose one over the other. I'd go for simplicity > and readability primarily - and that will depend on what error handling > is required etc. > > Jon >
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