builtin-functions.md

Built-in Functions

• see https://docs.python.org/3/library/functions.html

• print(*objects, sep=' ', end='/n')

• len(s) - length of string or collection

• type(obj)

• id(object) - object's identity ("hashcode")

• input([prompt]) - read value from CLI

• open(file) - read file

• range([start], stop, [step])

• reversed(seq) - reverse a sequence

• sorted(seq)

• eval(expr, globals, locals) - evaluate Python expression

  x = 100
  res = eval("x * 2")
  

Predicates

• all(iterable)
• any(iterable)

Math

• abs(x)
• max(args*), min(args*)
• pow(base, exp, [mod])
• round(number, [places])
• sum(iterable)

Type conversions & Numbers

• bin(x) - integer to binary string (bin(3) -> 0b11)
• bool([x]) - converts x to bool, see Truth Value Testing
• chr(i) - Unicode code point to string character
• complex([real, [imag]]) - complex numbers
• float([x])
• hex(x) - integer to hex string (bin(16) -> 0xa)
• int([x], base=10) - number or string to int
• ord(s) - string character to Unicode code point
• str(o) - object to string

Data structure factories

• bytearray
• bytes
• dict
• frozenset
• list
• set
• tuple

Code introspection

• dir([obj]) - names in the current scope, or object attributes (__dirs__)
• vars([obj]) - attributes and their values (__dict__)
• help(func) - function docs
• hasattr(obj, name),getattr(object, name), setattr(object, name, value)
• issubclass(class, classinfo),
• isinstance(obj, classinfo)

Streams

• map(func, iterable) - supports multiple iterables -> multiple arguments for the function
  • accepts iterable, returns iterator (aka map object)
• filter(func, iterable)
• zip(*iterables)