This time, in the third installment in this series, we're going to start delving deeper into working with strings of text and lists of words. But first, we need to learn how to write a program.

Up until now, we've been typing code directly into the Python interpreter. This is sometimes a convenient thing to do, as it's very easy to test a few lines of code to see if you get the desired result. However, as we want to create more complex programs it's going to be annoying to have to type everything from scratch every time we want to repeat a task. Thus, we will write programs.

Writing a program in python is no more complicated than writing code into a text file, and storing it with the .py file extension. For this task, you can use any program that can edit plain text, such as notepad on Windows or TextEdit on Mac, though I recommend that you get an editor which supports syntaxt highlighting. If you want to really become a serious hacker I recommend vim of course, but other good alternatives are TextMate for Mac, Sublime Text for Windows, Mac and Linux, Notepad++ for Windows, and many more. Do a little searching, perhaps watch some videos or something, and find one that suits you.

Assuming that you now have the editor in place, let's write our first program. Open a file, type

I still remember the moment when I discovered that George Sand and Frederic Chopin were lovers. There is something about the unexpected link between two people who are each already established in my brain with their own specific contexts and labels, neither of which contains the other.

That is how I felt when I discovered Charles Dickens and H.C. Andersen had met. The one belongs to British Victoriana, and is of course surrounded by all sorts of PhD-related associations for me; the other belongs to the Scandinavian, fairy tales and my childhood. I knew they lived more or less at the same time, at least I would have if someone asked; but they would never be linked in my mind.

The most delicious part of the story, however, is not that they met; but how soon Dickens got tired of Andersen once he came to visit and wouldn't leave.

I believe it is conventional to start at the beginning. The two first met in 1847, from what I can tell, during Andersen's trip to England. That year, Andersen dedicated his A Christmas Greeting to Dickens (incidentally, I believe this is where the Tin Soldier first makes an appearance; Dickens declared it one of his favourites in a letter to Andersen the following January). Afterwards, they exchanged letters. It was all very amicable.

But then, almost ten years later, in the summer of 1857, Andersen made the mistake of taking Dickens up on his invitation to come stay ...

Continuing from part 1 of this series, we'll be talking about lists and the for loop. There will be no recap, so read up on the last installment if neccessary.

Another way to create a list is with the range function, which creates a list of integers:

You'll notice that this list contains the 10 first integers, starting from 0 and ending up at 9. You might perhaps have expected the numbers from 1 to 10, but this all ties in with the zero-indexing, i.e., that the index of the first element in a list is 0. However, range can also produce other ranges, for example if you want the list to start at something other than 0, than give the number you want to start at first:

By the way, you might be wondering what range actually is, and the answer is that it is a built in function. We'll get back to functions, but for now let's just say that they are called by typing their name followed by the paranthesis, and the things inside the paranthesis are called arguments.

A third way to create lists, which will come in handy when we start looking at text, is to split up a string of text into smaller pieces. For example, let's define a variable holding some text:

I don't know if it's because I talk about programming a lot, or because digital humanities is all the rage and some programming skills seem like a good thing to have on one's resumé or if it's just intellectual curiosity, but for whatever reason, my wife, doctor of English literature, has decided that I should teach her to program. I've been thinking for some time that it would be fun to write a book to introduce humanities people to Python, so I'll be taking notes. If the notes are any good, and the project is a success, i.e., my wife learns to program, I might try to turn them into a manuscript. For the being, what you are currently reading is the first installment in my series of notes. Expect more at irregular intervals.

First things first: You need a terminal and a Python installation. If you are running linux, or have a computer form The House of Jobs, then you already have these things. If you are running Windows, I would suggest that you go home and rethink your life, but if that seems like too much effort you can also just go to the Python website and download a suitable version.

We'll start out by playing around in the Python shell, also known as the Python interpreter. To access this, you need to open your terminal application, and type (and press enter. Whenever I say to type something, you ...

Today I have learnt to create an elephant at the touch of a button. And to find Tor in a list. Not to mention the delight of turning a string into a list.

Confused? Me too.

I was especially discombobulated (I am taking refuge in friendly words) by Tor's assumption that I would know how f(x) worked (I associate it with differentiation and therefore with annoyance and pain, neither of which are conducive to happy learning).

Everything got much better once I managed to get him to admit that when he was talking about variables, he was really just talking about algebra (or at least algebra as it is defined in my brain; I always found it to be the friendliest branch of mathematics because it managed to avoid those pesky numbers, and I would ask you to not take this illusion away from me by explaining algebra beyond a high school level).

First thing's first: I set up my terminal to look cool. I instantly felt like a hardcore hacker.
We decided I should learn Python, because apparently Python is friendly and nice and will give me warm, cuddly feelings any moment now.

Tor then explained about functions and variables, and how variables can be anything from text strings (he seems obsessed with 'elephant' as a word -- I got much more excited when I realised text strings could include whole works of literature) to numbers (of all shapes and sizes -- I am less excited about them ...

Coding, to me, has always seemed rather unapproachable. A little bit like magic. Not the fun "as much chocolate as you could ever want, for free!" kind of magic; rather, a way in which to accomplish things that I could never hope to master. I know how to count in binary (of all the useless skills in the world); I am fascinated by programming languages (without really understanding them); I'll happily read books on the Difference Engine or the Enigma machine (although that may in part be due to my fascination with Lovelace and Babbage and Alan Turing); and I'll admit to sometimes staring at my iPhone in a sort of gleeful "how? HOW did you do that?" kind of way, while my mind tries to connect ContreJour with the opening and closing valves of 0 and 1 (who doesn't?).

I have always preferred books to computers, and my fear that the machine would die (possibly taking me with it) if I accidentally pushed the wrong sequence of buttons has entertained (and possibly frustrated?) Tor immensely. Much as I love technology that makes my life easier, I have had a (healthy) respect for the digital. You know where you stand with books. Unless you set fire to them or drop them in water, they will not accidentally get rid of your text; the worst they can do to you is give you a paper cut or fall on your head.

There may, however, be something in the ...

Her en dag hadde jeg behov for å bytte ut et par tegn i en tekststreng, og siden dette ikke akkurat er en innebygget funksjon i fortran bestemte jeg meg for å skrive min egen. Men først, hva betyr det egentlig å bytte ut et par tegn i en tekststreng?

En tekststreng, eller en string som man sier på engelsk, er rett og slett en serie med tegn som man kan håndtere i et programmeringsspråk. Jeg holder egentlig på å skrive en artikkel om datatyper, og da kommer jeg litt tilbake til dette, men for øyeblikket kan vi tenke på det som bokstaver, tall og andre tegn, pakket i hermetegn. For eksempel:

er python-kode for å si at a er en variabel som inneholder teksten «elefant». Det jeg vil gjøre er å erstatte en substreng i denne strengen med en annen streng. Hvis jeg for eksempel erstatter 'e' med 'o' blir resultatet 'olofant'.

(Egentlig kunne jeg tenke meg å være veldig generell, så jeg skrev en funksjon som erstatter alle instanser av én substreng med en annen streng av vilkårlig lengde, men på grunn av mangelfull implementering av Fortran 2003 i GCC 4.7 (den støtter ikke variabler i allocate-statements for allokering av strenger, som så vidt jeg kan skjønne koker ned til at du må vite lengden på strengen når du kompilerer.) så jeg meg nødt til å begrense meg til å erstatte en substreng med en annen streng av samme lengde, slik at lengden på strengen ...

Aiaiai, for en påske! Jeg hadde ikke forventet allverden, tatt i betraktning at det var relativt lite snø i marka sist jeg var hjemme, men akkurat som i fjor stilte været opp og leverte varene. Det kom rundt 20-30 cm snø midt i uken, noe som førte til stedvis perfekte forhold, og gradestokken har stort sett holdt seg under null, med blå himmel og sol og gode greier. Hvis jeg skal være pirkete kunne jeg ønsket meg litt mer snø (det stakk opp en del stein her og der) og enda litt kaldere vær (føret var til tider litt ujevnt der sola tok godt), men da er jeg vanskelig. Vi er tross alt på Vestlandet i slutten av mars.



Jeg har regnet meg frem til at jeg har gått minst 16 skiturer i år, som antagelig gjør dette til den mest aktive skisesongen min på 15-20 år. Fredag og lørdag fikk jeg dessuten til opptil flere fine telemarksvinger, så det kan tenkes at dette med god teknikk på ski faktisk er en treningssak, og ikke magi som jeg tidligere har antatt. Jeg tror nok gårsdagens skitur ble avslutningen på sesongen, men jeg sier meg fornøyd, og satser på en minst like bra sesong neste år.

For et års tid siden ble jeg oppmerksom på at The Guardian hadde startet en kampanje for å forbedre IT-opplæringen i skolen i Storbritannia. Det høres jo ut som en knakende god idé, tenkte jeg, og bestemte meg for at dette burde jeg skrive et leserinnlegg om til en norsk avis. Jeg kom så langt at jeg bladde litt i en rapport om fremtiden til norsk eInfrastruktur, hvor et utvalg nedsatt av forskningsrådet kommer med anbefalinger om en rekke ting, blant annet at barn bør lære å programmere:

Computers are becoming nearly universally available in the schools, where they are used as instruments for reference, exercises, drills, and examinations. Starting quite early – say as early as third or fourth year, when some elementary mathematics has been mastered – they should be opened up for tinkering with. Starting with simple task automation, progressing to control structures, then conditional execution. By school-leaving age, everyone should know what an algorithm is and have some idea how to construct one.

Jeg slo dessuten opp læreplanen for matematikk fellesfag, som ser ut til å bety til og med første år på videregående, og fant følgende svulstige formulering, under «Grunnleggjande ferdigheiter»:

Å kunne bruke digitale verktøy i matematikk handlar om å bruke slike verktøy til spel, utforsking, visualisering og publisering. Det handlar òg om å kjenne til, bruke og vurdere digitale hjelpemiddel til problemløysing, simulering og modellering. I tillegg er det viktig å finne informasjon, analysere, behandle og presentere data med høvelege hjelpemiddel, og vere kritisk til ...

Camilla spurte hvordan jeg hadde det på jobb i går, og jeg sa jeg hadde det bra. Hun spurte om jeg ikke hadde noe mer å si enn at jeg hadde det bra, kanskje en morsom historie å fortelle eller noe, og etter å ha tenkt meg litt om kom jeg på at jeg opplevde noe litt småfestlig. Jeg advarte riktignok om at det neppe kom til å bli en klassisk anekdote, men mer en ting å småhumre over i riktig selskap.

Det begynte med at jeg prøvde å kompilere et stykke fortran jeg nettopp hadde gjort noen endringer i, og kompilatoren klagde over at int ikke hadde en type. Som vi vet er jo int en intrinsic i fortran, så den har åpenbart en type. Jeg hadde nettopp spurt en av mine kolleger om en rekke andre ting, så jeg tenkte jeg skulle prøve å finne ut av dette problemet på egenhånd. Man ønsker jo å fremstå som resurssterk og selvhjulpen.

Jeg googlet litt etter feilmeldinger om manglende type fra ifort, og Stack Overflow indikerte at i noen tilfeller kan det se ut som om det er funksjonen selv som mangler type, mens det egentlig er argumentet det er noe galt med. Aha, tenkte jeg, og konkluderte med at det sikkert var noe galt med kind-parameteren, så jeg endret begge argumentene til hardkodede heltall, og kompilerte på nytt til samme feilmelding. På dette tidspunktet kom en kollega gående forbi kontoret mitt, så jeg påkalte oppmerksomhet, og det viste seg ...