What coding mnemonics do you use?

https://news.ycombinator.com/item?id=6171869

by vickytnz • 13 years ago

27 87 13 years ago

news.ycombinator.com

What weird coding things do you have to use statements for or other weird tricks to remember? I can never remember < or >, and only remember that < is less than from years of typing (i=0; i<30; i++).

da02• 13 years ago

.unshift - makes it bigger. Longer word than .shift

.shift - makes it smaller. Shorter word than .unshift

ronaldx4• 13 years ago

I could never remember this until someone told me to imagine that an array is like a row of chairs at a cinema.

"Shift" will shift everyone up one, bumping someone off the start of the row.

hill794• 13 years ago

I never remember that . = class and # = id in CSS, so I use "say no to drugs" to remember that "hash is not class".

Perhaps a mnemonic which only really works in the North East of the UK where 'class' is colloquial slang for 'good'. Also not very good if you smoke pot, I guess.

nakkiel• 13 years ago

Strange one. FYI, "class" has the same meaning in French slang -- probably borrowed from you guys.

scrapcode2• 13 years ago

I think it's the other way around. I think you guys use _class_ as slang to _classy_: "pertaining to or characteristic of a (high) class," which comes from the literal sense of class, which comes from the French word _classer_.

I didn't know for sure, but I had that feeling knowing that most of the English language is borrowed from others, and not the other way around. (http://www.etymonline.com/index.php?allowed_in_frame=0&searc...)

raverbashing3• 13 years ago

Just remember that a hashtag points to something specific. A dot means nothing, so that's the least specific/most generic thing

vickytnz3• 13 years ago

I also took it to mean that it's not classy to smoke hash (i.e. 'you stay classy, San Diego' :D)

Toadsoup2• 13 years ago

I remember the difference between class and id by thinking someone is trying to "Pound an idea into your head" or rather "# an id"

pwg• 13 years ago

You might try a visual trick. Note that < and > look like "arrows" and "point" in a particular direction. There is a small end (the tip/point) and a large end (the open end). The vertical size of the point is "less than" the vertical size of open end. So if the point comes first (reading left to right) then the point is "less than" the opening (and the symbol means "less than"), but if the opening comes first (reading left to right), the opening is "greater than" the point (and the symbol means "greater than"). .

hill794• 13 years ago

I don't know if this is common, but I visualise numbers on a line which makes it amazingly easy to use the 'arrows' metaphor

  <  >

1 2 3 4 5

dasil003• 13 years ago

That seems ambiguous to me in several ways. There must be more semantics you are subconsciously depending on to clarify it.

MerreM• 13 years ago

Imagine the arrows are crocodiles. They always try and eat more.

1 < 2

4 > 1

If they're eating less, they're not happy crocodiles.

brainburn• 13 years ago

Or maybe as snork-eater-eaters

http://wharble.com/sites/default/files/Snork-Eater_Eater.jpg

haliphax• 13 years ago

Or the "is greater than" (>) is a crocodile's mouth, and "is less than" (<) is a bird's beak. The bird eats smaller food than an crocodile eats, and the crocodile eats bigger food than the bird eats.

RutZap• 13 years ago

I use the same visual trick (more or less, looking at < and > as arrows, or if you want, spears) but I visualise bigger numbers as more "powerful" numbers that poke the "weak", smaller numbers with the pointy bit :D That's how I imagined them when I was a small child and that's how I still "see" them :D

Numbers are cruel and ruthless :)

JonnieCache3• 13 years ago

You can make it even simpler than that: just put the big number next to the big end of the glyph and vice versa.

tome• 13 years ago

Oh, I didn't realise anyone didn't remember it that way! I remember being taught it, but just assumed everyone else was, I guess.

pubby• 13 years ago

I'm not convinced programmers even need a mnemonic for < and >. After all, they'll read and write those glyphs millions of times in their lifetime.

JonnieCache3• 13 years ago

At least for me, the metaphors that I used to learn the symbols as a child have become my enduring mental models of those constructions, even if they're not actually needed to recall them any more.

MichaelAza3• 13 years ago

Not a mnemonic per se but I have melodies for common code snippets.

"public static void Main(string[] args)", which is the default method signature for the main method in C#, is a hip-hop beat. SQL statements are always metal tunes. Javascript is usually indie pop.

suhailpatel• 13 years ago

I also have a melody for the default method signature in Java which is the same except a slight difference in case "public static void main(String [] args)"

JonnieCache3• 13 years ago

Please tell me you guys are actually singing the signature to a particular tune in your head like people sing the ABC song when they recite the alphabet. Because that is adorable.

Rapping arbitrary chunks of code could be a fun after-hours conference game.

zqfm• 13 years ago

Just out of curiosity, do you say "array of string" or "strings" or something else?

MichaelAza3• 13 years ago

Actually, I say "string" and then drop the bass for the square brackets.

Terretta• 13 years ago

Markdown hyperlink syntax:

  "squared circle" aka []() aka [word](http://link)

chriswaugh• 13 years ago

When working with axis - "X is a-cross"

test1235• 13 years ago

'Y to the sky!'

michaelmartin• 13 years ago

Wise up! ;) (Y's up)

hill794• 13 years ago

Yes! Another one I use

Chris20483• 13 years ago

" You have to run, before you can fly, You have to X, before you can Y ",

Rhyming reminder of which axis is vertical, and which horizontal...

Joeboy• 13 years ago

"dollar hat, dollar at" in Makefiles:

$(CC) -c $^ -o $@

PaulHoule• 13 years ago

< and > are pretty easy. The big side (the mouth) points to the larger number because that it what it wants to eat.

raverbashing3• 13 years ago

I learned this in school. Still effective.

But I never know which one is "smaller than" or "bigger than", I have to think a little bit

scrapcode2• 13 years ago

Or you're pointing (or poking fun) at the little guy.

jentulman3• 13 years ago

LoVe HAte when ordering psudeo classes in css for anchors*

  ":link, :visited, :hover, :active"

*may not be particularly weird or novel

brokentone• 13 years ago

I heard "Las Vegas Hells Angels" and it's stuck with me.

jentulman3• 13 years ago

That's far more rock'n'roll, I might make the switch. Now I just need to remember...

'Naughty Llama Holidaymakers Book Lovely Vacation Homes from AirBNB'

= N.L.H.B.L.V.H.A = 'not Love Hate but Las Vegas Hells Angels'.

halisaurus• 13 years ago

Also CSS related, when doing margin/padding I use "TRouBLe" to remember:

    margin: (T R B L)

jentulman3• 13 years ago

My one is visualising a clock face, 12, 3, 6, 9

shousper2• 13 years ago

Do you have one for border-radius? Because I still can't remember the order of those..

Toadsoup2• 13 years ago

That's the one I use as well.

Although I can never remember the 3 parameter verision

margin: (T R&L B)

raverbashing3• 13 years ago

Not related to programming but close

The symbol for a diode is something like this: --|>|--

Now, which one is the Anode, which one is the Cathode

Very simple, the Anode has an A in the drawing (left side, turned 90 degrees), the Cathode (K) has a K, right side, upside down in the drawing

ronaldx4• 13 years ago

The fact that programmers can't remember < and > well illustrates why children shouldn't be chastised for getting (for example) b and d wrong.

I have dealt with this by conditioning myself to always read < as 'is less than'

afandian2• 13 years ago

I find it hard to believe that a statistically normal programmer mixes up < and >. That sounds more like dyslexia.

ronaldx4• 13 years ago

I was surprised to see that as an example as well, but then I thought back to starting out as a programmer.

I'm sure I spent many hours fixing bugs caused by getting < and > wrong.

yogo• 13 years ago

This is the first time I'm hearing about this too so I think there is more to it. I don't even see why a mnemonic is required since the shape of both '<' and '>' clearly demonstrate the relationship that the operator is testing.

thedudemabry• 13 years ago

I've known a few otherwise non-dyslexic programmers that have had this issue. One guy kept a sticky note on his monitor with "> Greater, < Less" written on it.

llcoolv• 13 years ago

specifically for this one, I have the mnemonic that the side containing the lower value has only one vertex, while the higher has 2 :)

milliams• 13 years ago

Yeah, the smaller end of the triangle is the smaller number and the wider end is the larger number.

chewxy• 13 years ago

Interesting. So other people too do get it mixed up. Makes me feel less silly when I find bits of my own code that looks like `x := >- receiverChannel`

I've always thought it's because of carelessness

kelvich• 13 years ago

Teacher in elementary school taught me simple rule: signs < and > has two endings on one side and one ending (corner) on another. So two bigger than one and bigger number should be on side with two endings.

rwbcxrz• 13 years ago

Mine taught us that it was an alligator, and it always wanted to eat the bigger number.

norvig• 13 years ago

When I was in grad school a friend in another department said "You guys in CS have much nicer printers; can I mail you my thesis and have you print it out? And how would I mail it?" I said "Sure; Just do 'mail me@school.edu less-than-symbol filename". Later he calls in a panic -- "my thesis file has disappeared! I did what you said ... oh, wait a minute, I might have done greater-than instead of less-than..."

Fortunately for both of us, he had been diligent about making backups and din't lose his entire thesis.

leigh_t• 13 years ago

\r\n or \n\r?

ReturN - R before N

informatimago• 13 years ago

Carriage Return is first because it takes much more time for the carriage to go back to the column 0 from the column 79, than for the paper to Line Feed one line. So while the carriage is flying back, the paper can feed, and hopefully we won't have to wait too much time for everything to be ready for a new line. Or we may always insert some Nul codes to wait.

CJefferson• 13 years ago

Most methods in C read like an assignment,

so if you are trying to remember what order the arguments to strcpy go, it's

    strcpy(x,y) is like x = y

Then remember specially that typedef is the wrong way around to the way you would like it to be :)

belovedeagle2• 13 years ago

The trick with typedef is it is exactly the same syntax, in all cases, as declaring a variable of that type. This is essentially the only way you're going to ever remember how to do function pointer typedefs: typedef int (function_t)(int,int); // or something to that effect

billb2112• 13 years ago

I was taught the alligator/crocodile thing like many others, but it never really stuck. For some reason (later in life), someone said "left hand, less than" as they held up their left hand to form a less than sign. That image sticks in my head a lot better.

Another thing that was particularly hard to get naturally was the ternary operator. It didn't sink in easily until Jon Skeet said pretend the ? is indeed a question. If the answer is 'yes', this will happen.

burgeralarm• 13 years ago

When using ln to link files, I tend to recite:

ln -s "what you want," "where you want it"

lostdog• 13 years ago

Another way to remember, is that ln behaves the same as cp

print2• 13 years ago

sounds like you may need lns:

http://interglacial.com/~sburke/pub/lns.html

anonymous2• 13 years ago

I don't use mnemonics in general. For me the effort to remember the mnemonic is actually double that for remembering the thing per se. I need to once remember the symbols->mnemonic connection and then the mnemonic->meaning connection, instead of simply the direct symbols->meaning one. It feels like cluttering my brain with junk that not only doesn't make it easier to remember things, it actively makes it harder.

ChristianMarks• 13 years ago

For the right-hand rule, a vile insult: take the cross-product of the thumb and forefinger of your right hand and rotate on it.

Look, Joshua Foer says that emotional imagery is more likely to stick...

anotherhue2• 13 years ago

Questionably coding, but I always loved this IRC snippet:

<sdmkun> tar -xzf merc.tgz what the fuck

<sdmkun> how the fuck do you people remember this shit

<bucketmouse> just think with a german accent

<bucketmouse> XTRACT ZE FILES

belovedeagle2• 13 years ago

I really don't see what the big deal is with tar. Everyone seems to hate it. Probably because exactly one of those flags is necessary: zcat merc.tgz | tar -x

anotherhue2• 13 years ago

I quite like it, and have almost a singalong bit for the meaning attached to each character I add to a long tar command

tar - [create] [verbosely] [a g/bzip'd compressed] [file named] foo.tgz (from) input_dir

tar -cvzf foo.tgz input_dir

Your version doesn't seem as 'fun', I guess zcat and PIPE are just hard to rhyme along to.

print2• 13 years ago

Don't memorize. Use unp:

http://packages.debian.org/unstable/utils/unp

ANTSANTS• 13 years ago

Or dtrx:

http://packages.debian.org/unstable/utils/dtrx

3minus1• 13 years ago

backslash is a man falling backwards. forwardslash is the opposite.

What coding mnemonics do you use?

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