Idioms and Style (CSCI-UA.0002

What's an idiom?

an idiom can be:
- a saying or expression whose meaning is not obvious from its individual parts
- an expression that is natural to a language
generally native speakers, or people who know the language, know the idioms
- it's raining cats and dogs
- hace mucho frío
- les carottes sont cuites

BTW, does anyone know the literal and idiomatic translations for these sayings?

An idiom in a programming language is:

a common task, computation, or construct that's expressed in a way that's unique, peculiar to or encouraged by the particular programming language in use
usually only those who use the language often know the idiomatic way to express things…
shows knowledge of the language, culture, and conventions / norms

multiple ways to express something, but language or community of language users prefer the idiomatic way
not necessarily formally specified
does not have to be followed
- if idioms are not used, program can still run
- if you don't do it idiomatically, you won't cause errors

in Python, there are a few ways to check if a value is in a list of values; two are shown below
both achieve the same result, but the second version is preferred

#  one way to do it; check each value
if name == 'Kermit' or name == 'Gonzo' or name == 'Skeeter':
    print(name + ' is a muppet!')

#  the idiomatic way; check for membership in a list
muppets = ['Kermit', 'Gonzo', 'Skeeter']
if name in muppets:
    print(name + ' is a muppet!')

(we'll look at lists later in the semester)

you'll probably spend as much time reading code as writing it:
1. code you've written
2. example code from books, specifications, forums, etc.
3. other people's code (collaboration, inherited code, etc.)
if everyone follows the same style, it'll be easier to read and edit existing programs

if answer == 5:
    print('correct')!

x = 2
y = 5

print("x plus y is ...")
print(x + y)

#  do this:
count = count + 1
#  *not* this:
count=count+1

#  do this:
count = 0
#  *not* this:
Count=0

#  do this:
my_count = 1
#  *not* this:
mycount = 1
myCount = 1

Idioms and Style