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用正确的形式填空1 I want ( )（put）these in the box.2 This table is too heavy.I can't( )(carry)it.3 Let's( )(take)the twins to the classroom.4 Could you ( )(help)me?5 There ( )(be)a pencil and two books on the desk.6 Let me ( )(have)a look.
用正确的形式填空1 I want ( )（put）these in the box.2 This table is too heavy.I can't( )(carry)it.3 Let's( )(take)the twins to the classroom.4 Could you ( )(help)me?5 There ( )(be)a pencil and two books on the desk.6 Let me ( )(have)a look.7 Dave ( )(like)to watch TV all night.8 My mother is vwry strict and ( )(make)me vwry tired.9 When( )he( )(have)art?10 My father likes ( )(read)newpapers at night.
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to put carrytake helpishavelikesmakesdoes,havereadingTeach Yourself Programming in Ten Years
Teach Yourself Programming in Ten Years
Peter Norvig
Why is everyone in such a rush?
Walk into any bookstore, and you'll see how to Teach Yourself Java
in 24 Hours alongside endless variations offering to teach C,
SQL, Ruby, Algorithms, and so on in a few days or hours.
The Amazon advanced search for [ and found 512 such books. Of the top ten, nine are programming books (the other is about bookkeeping). Similar results come from replacing "teach yourself" with "learn" or "hours" with "days."
The conclusion is that either people are in a big rush to learn
about programming, or that programming is somehow fabulously easier to
learn than anything else.
Felleisen et al.
give a nod to this trend in their book , when they say
"Bad programming is easy. Idiots can learn it in 21 days,
even if they are dummies." The Abtruse Goose comic also had .
Let's analyze what a title like
could mean:
Teach Yourself: In 24 hours you won't have time to write several
significant programs, and learn from your successes and failures with
You won't have time to work with an experienced programmer and
understand what it is like to live in a C++ environment.
In short, you
won't have time to learn much.
So the book can only be talking about a
superficial familiarity, not a deep understanding. As Alexander Pope said,
a little learning is a dangerous thing.
C++: In 24 hours you might be able to learn some of the syntax of
C++ (if you already know another language), but you couldn't
learn much about how to use the language.
In short, if you were, say, a
Basic programmer, you could learn to write programs in the style of
Basic using C++ syntax, but you couldn't learn what C++ is
actually good (and bad) for.
So what's the point?
Perlis once said: "A language that doesn't affect the way you
think about programming, is not worth knowing".
One possible point is
that you have to learn a tiny bit of C++ (or more likely, something
like JavaScript or Processing) because you need to interface with an
existing tool to accomplish a specific task. But then you're not
lea you're learning to accomplish that task.
in 24 Hours: Unfortunately, this is not enough, as the next
section shows.
Teach Yourself Programming in Ten Years
Researchers (Bloom
(1985), , Hayes
(1989), ) have shown it
takes about ten years to develop expertise in any of a wide variety of
areas, including chess playing, music composition, telegraph
operation, painting, piano playing, swimming, tennis, and research in
neuropsychology and topology.
The key is deliberative
practice: not just doing it again and again, but challenging yourself
with a task that is just beyond your current ability, trying it,
analyzing your performance while and after doing it, and correcting
any mistakes.
Then repeat.
And repeat again.
There appear to be no
real shortcuts: even Mozart, who was a musical prodigy at age 4, took
13 more years before he began to produce world-class music.
another genre, the Beatles seemed to burst onto the scene with a
string of #1 hits and an appearance on the Ed Sullivan show in 1964.
But they had been playing small clubs in Liverpool and Hamburg since
1957, and while they had mass appeal early on, their first great
critical success, Sgt. Peppers, was released in 1967.
has popularized the idea, although he concentrates on 10,000 hours rather than 10 years.
It may be that 10,000 hours, not 10 years, is the magic number. Or it might be
Henri Cartier-Bresson () said "Your first 10,000 photographs are your
True expertise may take a lifetime:
Samuel Johnson () said "Excellence in any department can be
attained only by the it is not to be purchased at
a lesser price."
And Chaucer () complained "the lyf so short, the craft
so long to lerne." Hippocrates (c. 400BC) is known for the excerpt "ars longa,
vita brevis", which is part of the longer quotation "Ars longa, vita
brevis, occasio praeceps, experimentum periculosum, iudicium
difficile", which in English renders as "Life is short, [the] craft
long, opportunity fleeting, experiment treacherous, judgment
difficult."
Of course, no single number can be the final answer: it doesn't seem reasonable
to assume that each of programming, chess playing, checkers playing, and music playing
could all require exactly the same amount of time to master, nor that all people
will take exactly the same amount of time.
So You Want to be a Programmer
Here's my recipe for programming success:
Get interested in programming, and do some because it is fun.
that it keeps being enough fun so that you will be willing to put in your ten years/10,000 hours.
The best kind of learning is learning
To put it more technically, "the maximal level of
performance for individuals in a given domain is not attained
automatically as a function of extended experience, but the level of
performance can be increased even by highly experienced individuals as
a result of deliberate efforts to improve." (p. 366)
and "the most effective learning requires a well-defined task with an
appropriate difficulty level for the particular individual,
informative feedback, and opportunities for repetition and corrections
of errors." (p. 20-21)
is an interesting
reference for this viewpoint.
Talk with read other programs.
This is more important
than any book or training course.
If you want, put in four years at a college (or more at a
graduate school).
This will give you access to some jobs that require
credentials, and it will give you a deeper understanding of the field,
but if you don't enjoy school, you can (with some dedication) get
similar experience on your own or on the job. In any case, book learning alone won't
be enough. "Computer science education cannot make anybody an expert
programmer any more than studying brushes and pigment can make
somebody an expert painter" says Eric Raymond, author of The New
Hacker's Dictionary. One of the best programmers I ever hired had
only a High S he's produced a lot of great software, has his own news group, and made enough in stock options to buy his own .
Work on projects with other programmers. Be the best programmer
be the worst on some others.
When you're the best,
you get to test your abilities to lead a project, and to inspire
others with your vision.
When you're the worst, you learn what the
masters do, and you learn what they don't like to do (because they
make you do it for them).
Work on projects after other programmers.
Understand a program written by someone else. See what it takes to
understand and fix it when the original programmers are not
around. Think about how to design your programs to make it easier for
those who will maintain them after you.
Learn at least a half dozen programming languages.
Include one
language that emphasizes class abstractions (like Java or C++), one that
emphasizes functional abstraction (like Lisp or ML or Haskell), one
that supports syntactic abstraction (like Lisp), one
that supports declarative specifications (like Prolog or C++
templates), and
one that emphasizes parallelism (like Clojure or Go).
Remember that there is a "computer" in "computer science". Know
how long it takes your computer to execute an instruction, fetch a
word from memory (with and without a cache miss), read consecutive words from disk, and seek to a new location on disk. ()
Get involved in a language
standardization effort.
It could be the ANSI C++ committee, or it
could be deciding if your local coding style will have 2 or 4 space
indentation levels.
Either way, you learn about what other people
like in a language, how deeply they feel so, and perhaps even a little
about why they feel so.
Have the good sense to get off the language standardization effort as
quickly as possible.
With all that in mind, its questionable how far you can get just by
book learning.
Before my first child was born, I read all the How
To books, and still felt like a clueless novice.
30 Months later,
when my second child was due, did I go back to the books for a
refresher? No.
Instead, I relied on my personal experience, which
turned out to be far more useful
and reassuring
to me than the thousands of pages written
by experts.
Fred Brooks, in his essay
identified a three-part plan for finding great
software designers:
Systematically identify top designers as early as possible.
Assign a career mentor to be responsible for the development of the prospect and carefully keep a career file.
Provide opportunities for growing designers to interact and stimulate each other.
This assumes that some people already have the qualities necessary for
be the job is to properly coax them along.
Perlis put it more succinctly: "Everyone can be taught to sculpt:
Michelangelo would have had to be taught how not to. So it is with the
great programmers".
Perlis is saying that the greats have some
internal quality that transcends their training.
But where does the
quality come from?
Is it innate?
Or do they develop it through
diligence?
As Auguste Gusteau (the fictional chef in
Ratatouille) puts it, "anyone can cook, but only the fearless
can be great."
I think of it more as willingness to devote a large
portion of one's life to deliberative practice.
fearless is a way to summarize that. Or, as Gusteau's critic,
Anton Ego, says: "Not everyone can become a great artist, but a great
artist can come from anywhere."
So go ahead and buy that Java/Ruby/Javascript/PHP you'll
probably get some use out of it.
But you won't change your life, or
your real overall expertise as a programmer in 24 hours or 21 days.
How about working hard to continually improve over 24 months?
Well, now you're starting to get somewhere...
References
Bloom, Benjamin (ed.) , Ballantine, 1985.
Brooks, Fred, , IEEE Computer, vol. 20, no. 4, 1987, p. 10-19.
Hayes, John R.,
Lawrence Erlbaum, 1989.
Cognitive Psychology, -81.
Lave, Jean, , Cambridge University Press, 1988.
Approximate timing for various operations on a typical PC:
execute typical instruction 1/1,000,000,000 sec = 1 nanosec
fetch from L1 cache memory 0.5 nanosec
branch misprediction 5 nanosec
fetch from L2 cache memory 7 nanosec
Mutex lock/unlock 25 nanosec
fetch from main memory 100 nanosec
send 2K bytes over 1Gbps network 20,000 nanosec
read 1MB sequentially from memory 250,000 nanosec
fetch from new disk location (seek) 8,000,000 nanosec
read 1MB sequentially from disk 20,000,000 nanosec
send packet US to Europe and back 150 milliseconds = 150,000,000 nanosec
Appendix: Language Choice
Several people have asked what programming language they should learn first.
There is no one answer, but consider these points:
Use your friends. When asked "what operating system should
I use, Windows, Unix, or Mac?", my answer is usually: "use whatever
your friends use."
The advantage you get from learning from your
friends will offset any intrinsic difference between OS, or
between programming languages.
Also consider your future friends:
the community of programmers that you will be a part of if you
Does your chosen language have a large growing community
or a small dying one?
Are there books, web sites, and online forums
to get answers from?
Do you like the people in those forums?
Keep it simple.
Programming languages such as C++
and Java are designed for professional development by large teams of
experienced programmers who are concerned about the run-time efficiency of
their code.
As a result, these languages have complicated parts designed for these circumstances.
You're concerned with learning to program.
You don't need that complication.
You want a language that was designed to be easy to learn and remember by a
single new programmer.
Play. Which way would you rather learn to play the piano: the
normal, interactive way, in which you hear each note as soon as you hit a key,
or "batch" mode, in which you only hear the notes after you finish a whole song?
Clearly, interactive mode makes learning easier for the piano, and also for
programming. Insist on a language with an interactive mode and use it.
Given these criteria, my recommendations for a first programming
language would be
Another choice is Javascript, not because it is perfectly well-designed for beginners,
but because there are so many online tutorials for it, such as
circumstances may vary, and there are other good choices. If your
age is a single-digit, you might prefer
(older learners might also enjoy these). The important
thing is that you choose and get started.
Appendix: Books and Other Resources
Several people have asked what books and web pages they should learn
I repeat that "book learning alone won't be enough" but I can
recommend the following:
Scheme: Structure and
Interpretation of Computer Programs (Abelson & Sussman) is
probably the best introduction to computer science, and it does
teach programming as a way of understanding the computer science.
You can see
on this book, as well as the . The book is
challenging and will weed out some people who perhaps could be
successful with another approach.
is one of the best books
on how to actually design programs in an elegant and functional way.
is a good introduction using Python.
Python: Several
are available at .
is seen by some as the modern-day successor to Abelson & Sussman.
It is a tour through the big ideas of programming, covering a wider
range than Abelson & Sussman while being perhaps easier to read and
It uses a language, Oz, that is not widely known but serves as
a basis for learning other languages.
T. Capey points out that the Complete
Problem Solver page on Amazon now has the "Teach Yourself
Bengali in 21 days" and "Teach Yourself Grammar and Style" books under the
"Customers who shopped for this item also shopped for these items"
I guess that a large portion of the people who look at that
book are coming from this page.
Thanks to Ross Cohen for help with Hippocrates.
&&&&&&&&&&
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following authors,
translations of
this page are
available in:Put Down Your E-Reader: This Book Is Better In Print : NPR
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The author, illustrator and publisher of a richly illustrated retelling of Homer's The Odyssey say that not all books can be e-books. "E-books are fine for the things e-books are good for," says author Gillian Cross, "but they couldn't do this at all."
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Neil Packer/Candlewick Press
Most people who read a lot have gotten used to reading on a screen, whether it's a laptop, a tablet or an e-reader. Some say they prefer it to the experience of reading a heavy, awkward print version of the book. But every now and then, a book comes along that just seems to insist on being physical — something about it simply can't be transferred to the screen.
More on this book:
Gillian Cross' new retelling of Homer's The Odyssey is aimed at kids 8 and up, and like many children's books, it's brightly colored and beautifully illustrated. But the artwork in this book — illustrated by Neil Packer — seems sophisticated for a kids' book. These are not your standard depictions of gods and goddesses with chiseled features in flowing gowns. The images are stylized, multilayered, richly colored and a little edgy. It seems like a book that might appeal to adults as well as children — a perfect book perhaps to read with a child. Would a book like this ever make sense as an e-book?
"We feel that the book is a nearly perfect technology as it is, and that is why it's been around for so long," says Karen Lotz, president and publisher of Candlewick Press — the publishing house that released The Odyssey in the U.S. Candlewick specializes in children's books, and like all publishing companies, it now releases books in both electronic and traditional book form. But Lotz says some books — The Odyssey among them — seem destined for print. That decision, she says, is made at the beginning of the publication process.
"If you're thinking about a book in its early stages, you're almost always imagining what it's going to be like and what it's going to feel like," Lotz explains. "And I think we're coming into a time where we as publishers do that digitally as well. We think about something in a digital form. But if it's going to insist on being physical, it means it's going to be lavish, beautiful, tactile, something to linger over."
"It was war that forced Odysseus to leave his home ... Odysseus wanted to stay on Ithaca with his own wife, Penelope, and their baby son, Telemachus. But the other kings needed his quick wits and his cunning."
Neil Packer/Candewick Press
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Neil Packer/Candewick Press
"It was war that forced Odysseus to leave his home ... Odysseus wanted to stay on Ithaca with his own wife, Penelope, and their baby son, Telemachus. But the other kings needed his quick wits and his cunning."
Neil Packer/Candewick Press
Lotz says at Candlewick they strive to make every book beautiful, but a few fall into a category they think of as their "specials" line. These are books that might make good gifts or that they imagine will have a long life on someone's library shelf. A team of editors, art directors and designers lavish attention on these books, paying close attention to every detail during production.
"We're all obsessed actually with books, with paper, with paper quality," Lotz says. "We've gone so far on certain of our titles to invent colors that never existed before. ... That's the type of detail that we're into. We love working with the artist and figuring out what their dream would be of the ideal form, and that kind of collaboration is incredibly exciting."
Neil Packer, the artist behind The Odyssey, has also illustrated collectors' editions of well-known novels including Catch-22 and One Hundred Years of Solitude. Packer says he began working on The Odyssey six years ago, well before most people had even heard of e-books.
"It was very much conceived, obviously, as a tactile and physical thing," Packer says. "I work pigment on paper — that's how the thing starts, and that's probably how they are best represented. For me, I like the tactility of the book and that fact that one can have it as on object of beauty, almost an ornament."
"He and his men traveled on across the uncharted sea, congratulating themselves on their escape. They were still lost, but they let the wind carry them forward, hoping they would soon reach land."
Neil Packer/Candlewick Press
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Neil Packer/Candlewick Press
"He and his men traveled on across the uncharted sea, congratulating themselves on their escape. They were still lost, but they let the wind carry them forward, hoping they would soon reach land."
Neil Packer/Candlewick Press
Packer says he would be interested in exploring what he could do with digital technology, but he believes if a book is going to be viewed on screen, the artwork needs to be conceived that way. He says transferring artwork from the pages of a book like The Odyssey to an electronic device doesn't really work.
"I don't think turning it into an electronic book would actual it wouldn't bring anything to it," he says. "The problem is with picture books, when you put them on a screen, they sit there rather awkwardly. They don't actually do anything. I think the temptation for publishers then is often to add animation to them and open up discussion forums and that sort of thing — again, it doesn't ... take them anywhere."
Of course, illustrations alone do not make a book, especially a book like The Odyssey. "The book was conceived as a whole, words and pictures together — they're not separable," says writer Gillian Cross.
Cross wrote this version of The Odyssey for children. She views the book as a stepping stone, a way in for young people who are likely to read the original when they get older. Cross says she can't imagine The Odyssey in e-book form.
"For two days and nights, Odysseus was alone in the wild water. The sea was so rough that he couldn't see beyond the nearest wave. Over and over again, he thought he was going to die."
Neil Packer/Candlewick Press
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Neil Packer/Candlewick Press
"For two days and nights, Odysseus was alone in the wild water. The sea was so rough that he couldn't see beyond the nearest wave. Over and over again, he thought he was going to die."
Neil Packer/Candlewick Press
"I have known all along it would be impossible for it to be an e-book with the current state of the technology," Cross says. "There's no way the technology could cope with what the pictures are, with their richness and their vitality."
Cross has nothing but admiration for Packer's artwork, but she does disagree with him on one point: The beauty of a book is one reason to treasure it, she says, but a book should be viewed as more than a work of art that sits on a shelf. If it is regarded as nothing more than an ornament, she worries it will be marginalized, and readers of the future will never understand all that a physical book offers.
"With anything digital, even upon your e-reader, there will be another book, or on the Internet there will be another link you can click on," Cross says. "The fact that a printed book invites you to close it, and that it has been specially designed so that the shape of it might be unique — the shape of The Odyssey is quite interesting, isn't it? And the weight of it in your hands — all these things I think have value in that they invite you to reflect on what's inside the book."
"Athene made her way to King Alcinous's palace and found Nausicaa sleeping ... Disguising herself as one of Nausicaa's friends, she hovered over the princess's bed and whispered into her dreams."
Neil Packer/Candlewick Press
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Neil Packer/Candlewick Press
"Athene made her way to King Alcinous's palace and found Nausicaa sleeping ... Disguising herself as one of Nausicaa's friends, she hovered over the princess's bed and whispered into her dreams."
Neil Packer/Candlewick Press
Not all books are the same. Some, like encyclopedias and paperbacks we pick up while traveling navigate easily to the screen. But some books hold a special place in our hearts. Often, says Karen Lotz, they are the books we first encountered as children.
"People tend to remember the books that they had when they were children as physical objects," Lotz says. "They remember what the book felt like in their hand, where it sat in their room, they take it under the covers at night, they take it outside to read under a tree. It's a very precious object, it gets some power over us as we read it, it sort of becomes part of us and we become part of it in a very interesting way."
The technology of e-books is still developing, says Lotz. Eventually it may be possible to reproduce visually rich, highly designed books onto a screen in a way that is as satisfying as a physical book. But even when and if that day arrives, Lotz believes there will always be a place for both — and perhaps there will always be books that just don't need to go digital.
"... Gazing down from high Olympus: Zeus, the fa Athene,
Hermes, the giant killer and m and Poseidon, the dark earth-shaker god who controlled the ocean."
Neil Packer/Candlewick Press
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Neil Packer/Candlewick Press
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