Question

Just starting to figure Python out. I’ve read this question and its responses:

Is it true that I can't use curly braces in Python?

and I still can’t fathom how curly braces work, especially since pages like Simple Programs:

http://wiki.python.org/moin/SimplePrograms

use curly braces all over the place. I understand square brackets and regular curved parentheses, but I don’t know what’s meant by “defining dictionaries” or what they’re supposed to represent.

Answer 1

"Curly Braces" are used in Python to define a dictionary. A dictionary is a data structure that maps one value to another – kind of like how an English dictionary maps a word to its definition.

Python:

dict = {
    "a" : "Apple",
    "b" : "Banana",
}

They are also used to format strings, instead of the old C style using %, like:

ds = ['a', 'b', 'c', 'd']
x = ['has_{} 1'.format(d) for d in ds]

print x

['has_a 1', 'has_b 1', 'has_c 1', 'has_d 1']

They are not used to denote code blocks as they are in many "C-like" languages.

C:

if (condition) {
    // do this
}

Update: In addition to Python’s dict data types Python has (since Python 2.7) set as well, which uses curly braces too and are declared as follows:

my_set = {1, 2, 3, 4}