This one and the following ones in the series might actually be better: http://www.youtube.com/watch?v=T4Myub8sJH0
On Sat, May 12, 2012 at 3:03 PM, Laurent <laurent.ors...@gmail.com> wrote: > Hi Saad, > > I don't know if this is advisable in general, and hopefully I'm not making > a rookie teacher mistake here, but it seems that in your case you could use > some videos to get you started with the basics: > For example: http://www.youtube.com/watch?v=IwpnDJ45yLA > > There might be some little differences with the current version of > DrRacket though. > Other videos: > http://www.youtube.com/results?q=drracket > > This should help you start a little. After that, for the programming part, > it's probably better if you stick to HtDP. > > Cheers, > Laurent > > > On Sat, May 12, 2012 at 2:35 PM, saad bashir <bashir.s...@gmail.com>wrote: > >> Dear Matthias, >> >> Thank you for replying to me. I am sure this is laughably basic for you. >> >> I got what you wrote. I know string-ith extracts the letter. My >> question is how to use it. I have tried various ways of writing both in the >> def and interaction sections but have not worked out. Even consulting the >> Helpdesk has not helped as it does not tell me how to use the fucntion. >> >> Sorry if I am being very thick. I really want to do it right. >> >> Saad >> >> >> On Fri, May 11, 2012 at 11:47 PM, Matthias Felleisen < >> matth...@ccs.neu.edu> wrote: >> >>> >>> The beginning of section 2.1.3 looks like this: >>> >>> >>> > All other operations concerning strings consume or produce data other >>> than strings. Here are some examples: >>> > • string-length consumes a string and produces a (natural) >>> number; >>> > >>> > • string-ith consumes a string s and extracts the one-character >>> substring located at the ith position (counting from 0); and >>> > >>> > • number->string consumes a number and produces a string. >>> > >>> > Also look up substring and find out what it does. >>> >>> Which function do you think extracts a "letter" from a string? [[You can >>> follow the links for the function names. Perhaps it is easier to read the >>> docs.]] >>> >>> -- Matthias >>> >>> >>> >>> >>> On May 11, 2012, at 4:22 PM, saad bashir wrote: >>> >>> > I am back again. I had a basic inquiry and your help got me started. >>> > >>> > My problem is as follows: >>> > >>> > I have just started to work through 2Htdp (i.e. the second edition) >>> that you had guided me to. Having gone through the prologue I am now on the >>> second chapter, "Fixed-size data." But have got stuck almost at the start. >>> I have successfully done the first two exercises but have hit a road block >>> on exercise 3 (section 2.1.3 "Mixing it up"). I do not know what >>> instruction to use to insert or extract a letter from the ith position. I >>> think I am doing something wrong when trying to look up things in Helpdesk. >>> Please help. >>> > >>> > Saad >>> > >>> > On Fri, Apr 27, 2012 at 8:32 PM, Danny Yoo <d...@cs.wpi.edu> wrote: >>> > On Fri, Apr 27, 2012 at 11:27 AM, saad bashir <bashir.s...@gmail.com> >>> wrote: >>> > > Your help was great. Things are working now. And a great thank you >>> for >>> > > leading me to the 2d edition of How to Design Programs. I had not >>> known >>> > > about it. >>> > >>> > >>> > Glad to hear that it's working for you now! Please feel free to >>> > continue to ask questions on the mailing list; we'll be happy to help. >>> > >>> > ____________________ >>> > Racket Users list: >>> > http://lists.racket-lang.org/users >>> >>> >> >> ____________________ >> Racket Users list: >> http://lists.racket-lang.org/users >> >> >
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