Constructing Range and Ranges
You can create them from:
- strings
- range-like objects
- sequences of ints or these things, or other sequences
- explicitly, like you would create a
rangeorslice
Range from a string
from arranges import Ranges
# Create ranges from a string. Like a slice but without the square brackets.
the_full_range = Ranges(":") # an endless sequence starting at 0
the_empty_range = Ranges("") # start, stop and len() are all 0
from_0_to_99 = Ranges("0:100")
skip_10_items = Ranges("10:") # boundless, goes to infinity
access_by_index = Ranges("0") # just the first item
# Decimal, hexadecimal, octal and binary are supported. Note that octal uses
# Python's 0o prefix, not 0 like in C.
gbc_palette = Ranges("0xff68:0xff88")
skip_bmp_header = Ranges("0o66:end") # skip "54", "0x36" or "0b1100110" bytes
# "end" and "inf" are the same. You can also use "start" instead of 0.
the_full_range_again = Ranges("start:inf")
# whitespace is ignored during construction
first_kilobyte = Ranges("start : 0x400")
# They are simplified when converted to str, which they can be compared with.
assert first_kilobyte == ":1024"
# Comparisons work in both directions
assert "000001:000002" == Ranges("1")
# and the hash is the same as the string
w = Ranges("6 : 8")
assert hash(w) == hash("6:8")
# so you can use them as dict keys
d = {"6:8": "width"}
d[w] = "GIF file width"
assert d == {"6:8": "GIF file width"}
Ranges from a string
from arranges import Ranges
# You can put gaps in your range using commas.
pages_2_to_5_and_20 = Ranges("2:6, 20")
# The ranges are sorted and combined as they are added
overlapping = Ranges("start:10, 14, 1:3")
assert overlapping == ":10,14"
Ranges from range-like objects
If it has a start, stop and step attribute then it quacks like a range so you can pass it in as the value.
from arranges import Ranges
from_slice = Ranges(slice(10, 20))
from_range = Ranges(range(10, 20))
from_other = Ranges(Ranges("10:20"))
assert from_slice == from_range == from_other == "10:20"
Ranges from sequences
from arranges import Ranges
l = list(range(100))
t = tuple(range(100))
i = (i for i in range(100))
assert Ranges(l) == Ranges(t) == Ranges(i) == ":100"
jumble = Ranges([0, [2, 4], ["1:3"], 3, 4, range(10, 20)])
assert jumble == "5,10:20"
Explicitly creating Ranges
You can create them in the same way as range or slice objects which have a
slightly different syntax to slice notation.