What’s the Difference Between ( ), [ ], { } and < >?

( )

Parentheses (the single one is called a parenthesis), also known as curved brackets, have plenty of uses in everyday written language. Their most common use, as I’ve demonstrated already, is segregating subordinate material or asides. Usually, this is stuff that could be left out of the text or skipped over during reading without altering the flow or meaning of the surrounding sentence. You can do the same thing with commas, like I did in the last sentence and am doing now, but, if you’ve got a few commas in the sentence for other purposes, things can get a little out of hand, like they might be here.

In cases where a writer is uncertain whether a subject(s) is singular or plural, or male or female, and (s)he wants to cover all the bases, parentheses denote that things could be one or the other.

Parentheses also have a few uses in mathematics, and are used to denote sets of coordinates, set aside the arguments of functions and set precedence in the order of operations. You might remember the mnemonic device PEMDAS (or BODMAS or BEDMAS if you’re from the UK or Canada) from math class: in a calculation, you do the stuff in parentheses first, then exponents, then multiplication and division, and finally addition and subtraction (left to right on those last four).

[ ]

Square brackets are primarily used to modify quoted text by someone who isn’t the original author. These modifications might include…

  • Adding clarification - “He [the sheriff] shot them [the zombies] in the head.”
  • Adding missing information - “The zombies had come into the city from two adjoining counties [Butler and Beaver].”
  • Adding missing words - “Where [are] the zombies at?”
  • Adding editorial comment - “If you are bitten by a zombie, do not try to hide it from your fellow survivors.” [emphasis mine]
  • Adding an ellipsis or the Latin word sic to indicate deleted material or that the text is quoted exactly as it appeared in the original source - “Oh muh gawd [sic], the zombies are coming through the window […]”

Square brackets can also be used to nest subordinate text within subordinate text (this is done by putting square brackets [like these guys] inside parentheses).

In mathematics, square brackets are used to denote floor and ceiling functions, commutators, matrices, intervals and other things that I don’t understand.

{ }

Curly brackets, sometimes called squiggly brackets or braces, don’t see much use in everyday writing, but do pop up in poetry (to join triplet lines), music (to mark grace notes), math (to list members of a set) and different programming languages (to enclose groups of statements).

< >

Chevrons, or angle brackets, are also largely confined to specialized use. In programming markup language, like html, tags and other statements. In comic books, graphic novels and video games, they’re sometimes placed around dialog to indicate that the character is speaking another language and you’re reading the translation. On TV, they're sometimes placed around the names of sounds (<explosion>) to interpret sound effects in closed captions. In mathematical calculations they’re used to indicate that one number is less than or greater than another.

In more common usage, especially in online conversation, they’re used to make text hearts (<3) or indicate a writer’s physical actions <waves goodbye>.

Big Questions
What's the Difference Between Gophers and Groundhogs?
Gopher or groundhog? (If you chose gopher, you're correct.)
Gopher or groundhog? (If you chose gopher, you're correct.)

Gophers and groundhogs. Groundhogs and gophers. They're both deceptively cuddly woodland rodents that scurry through underground tunnels and chow down on plants. But whether you're a nature nerd, a Golden Gophers football fan, or planning a pre-spring trip to Punxsutawney, Pennsylvania, you might want to know the difference between groundhogs and gophers.

Despite their similar appearances and burrowing habits, groundhogs and gophers don't have a whole lot in common—they don't even belong to the same family. For example, gophers belong to the family Geomyidae, a group that includes pocket gophers (sometimes referred to as "true" gophers), kangaroo rats, and pocket mice.

Groundhogs, meanwhile, are members of the Sciuridae (meaning shadow-tail) family and belong to the genus Marmota. Marmots are diurnal ground squirrels, Daniel Blumstein, a UCLA biologist and marmot expert, tells Mental Floss. "There are 15 species of marmot, and groundhogs are one of them," he explains.

Science aside, there are plenty of other visible differences between the two animals. Gophers, for example, have hairless tails, protruding yellow or brownish teeth, and fur-lined cheek pockets for storing food—all traits that make them different from groundhogs. The feet of gophers are often pink, while groundhogs have brown or black feet. And while the tiny gopher tends to weigh around two or so pounds, groundhogs can grow to around 13 pounds.

While both types of rodent eat mostly vegetation, gophers prefer roots and tubers (much to the dismay of gardeners trying to plant new specimens), while groundhogs like vegetation and fruits. This means that the former animals rarely emerge from their burrows, while the latter are more commonly seen out and about.

Groundhogs "have burrows underground they use for safety, and they hibernate in their burrows," Blumstein says. "They're active during the day above ground, eating a variety of plants and running back to their burrows to safety. If it's too hot, they'll go back into their burrow. If the weather gets crappy, they'll go back into their burrow during the day as well."

But that doesn't necessarily mean that gophers are the more reclusive of the two, as groundhogs famously hibernate during the winter. Gophers, on the other hand, remain active—and wreck lawns—year-round.

"What's really interesting is if you go to a place where there's gophers, in the spring, what you'll see are what is called eskers," or winding mounds of soil, Blumstein says [PDF]. "Basically, they dig all winter long through the earth, but then they tunnel through snow, and they leave dirt in these snow tunnels."

If all this rodent talk has you now thinking about woodchucks and other woodland creatures, know that groundhogs have plenty of nicknames, including "whistle-pig" and "woodchuck," while the only nicknames for gophers appear to be bitter monikers coined by Wisconsin Badgers fans.

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Big Questions
Why Does Santa Claus Give Coal to Bad Kids?

The tradition of giving misbehaving children lumps of fossil fuel predates the Santa we know, and is also associated with St. Nicholas, Sinterklaas, and Italy’s La Befana. Though there doesn't seem to be one specific legend or history about any of these figures that gives a concrete reason for doling out coal specifically, the common thread between all of them seems to be convenience.

Santa and La Befana both get into people’s homes via the fireplace chimney and leave gifts in stockings hung from the mantel. Sinterklaas’s controversial assistant, Black Pete, also comes down the chimney and places gifts in shoes left out near the fireplace. St. Nick used to come in the window, and then switched to the chimney when they became common in Europe. Like Sinterklaas, his presents are traditionally slipped into shoes sitting by the fire.

So, let’s step into the speculation zone: All of these characters are tied to the fireplace. When filling the stockings or the shoes, the holiday gift givers sometimes run into a kid who doesn’t deserve a present. So to send a message and encourage better behavior next year, they leave something less desirable than the usual toys, money, or candy—and the fireplace would seem to make an easy and obvious source of non-presents. All the individual would need to do is reach down into the fireplace and grab a lump of coal. (While many people think of fireplaces burning wood logs, coal-fired ones were very common during the 19th and early 20th centuries, which is when the American Santa mythos was being established.)

That said, with the exception of Santa, none of these characters limits himself to coal when it comes to bad kids. They’ve also been said to leave bundles of twigs, bags of salt, garlic, and onions, which suggests that they’re less reluctant than Santa to haul their bad kid gifts around all night in addition to the good presents.

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