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| # Author: Fred L. Drake, Jr. | |
| # fdrake@acm.org | |
| # | |
| # This is a simple little module I wrote to make life easier. I didn't | |
| # see anything quite like it in the library, though I may have overlooked | |
| # something. I wrote this when I was trying to read some heavily nested | |
| # tuples with fairly non-descriptive content. This is modeled very much | |
| # after Lisp/Scheme - style pretty-printing of lists. If you find it | |
| # useful, thank small children who sleep at night. | |
| """Support to pretty-print lists, tuples, & dictionaries recursively. | |
| Very simple, but useful, especially in debugging data structures. | |
| Classes | |
| ------- | |
| PrettyPrinter() | |
| Handle pretty-printing operations onto a stream using a configured | |
| set of formatting parameters. | |
| Functions | |
| --------- | |
| pformat() | |
| Format a Python object into a pretty-printed representation. | |
| pprint() | |
| Pretty-print a Python object to a stream [default is sys.stdout]. | |
| saferepr() | |
| Generate a 'standard' repr()-like value, but protect against recursive | |
| data structures. | |
| """ | |
| import collections as _collections | |
| import re | |
| import sys as _sys | |
| import types as _types | |
| from io import StringIO as _StringIO | |
| __all__ = ["pprint","pformat","isreadable","isrecursive","saferepr", | |
| "PrettyPrinter"] | |
| def pprint(object, stream=None, indent=1, width=80, depth=None, *, | |
| compact=False): | |
| """Pretty-print a Python object to a stream [default is sys.stdout].""" | |
| printer = PrettyPrinter( | |
| stream=stream, indent=indent, width=width, depth=depth, | |
| compact=compact) | |
| printer.pprint(object) | |
| def pformat(object, indent=1, width=80, depth=None, *, compact=False): | |
| """Format a Python object into a pretty-printed representation.""" | |
| return PrettyPrinter(indent=indent, width=width, depth=depth, | |
| compact=compact).pformat(object) | |
| def saferepr(object): | |
| """Version of repr() which can handle recursive data structures.""" | |
| return _safe_repr(object, {}, None, 0)[0] | |
| def isreadable(object): | |
| """Determine if saferepr(object) is readable by eval().""" | |
| return _safe_repr(object, {}, None, 0)[1] | |
| def isrecursive(object): | |
| """Determine if object requires a recursive representation.""" | |
| return _safe_repr(object, {}, None, 0)[2] | |
| class _safe_key: | |
| """Helper function for key functions when sorting unorderable objects. | |
| The wrapped-object will fallback to a Py2.x style comparison for | |
| unorderable types (sorting first comparing the type name and then by | |
| the obj ids). Does not work recursively, so dict.items() must have | |
| _safe_key applied to both the key and the value. | |
| """ | |
| __slots__ = ['obj'] | |
| def __init__(self, obj): | |
| self.obj = obj | |
| def __lt__(self, other): | |
| try: | |
| return self.obj < other.obj | |
| except TypeError: | |
| return ((str(type(self.obj)), id(self.obj)) < \ | |
| (str(type(other.obj)), id(other.obj))) | |
| def _safe_tuple(t): | |
| "Helper function for comparing 2-tuples" | |
| return _safe_key(t[0]), _safe_key(t[1]) | |
| class PrettyPrinter: | |
| def __init__(self, indent=1, width=80, depth=None, stream=None, *, | |
| compact=False): | |
| """Handle pretty printing operations onto a stream using a set of | |
| configured parameters. | |
| indent | |
| Number of spaces to indent for each level of nesting. | |
| width | |
| Attempted maximum number of columns in the output. | |
| depth | |
| The maximum depth to print out nested structures. | |
| stream | |
| The desired output stream. If omitted (or false), the standard | |
| output stream available at construction will be used. | |
| compact | |
| If true, several items will be combined in one line. | |
| """ | |
| indent = int(indent) | |
| width = int(width) | |
| if indent < 0: | |
| raise ValueError('indent must be >= 0') | |
| if depth is not None and depth <= 0: | |
| raise ValueError('depth must be > 0') | |
| if not width: | |
| raise ValueError('width must be != 0') | |
| self._depth = depth | |
| self._indent_per_level = indent | |
| self._width = width | |
| if stream is not None: | |
| self._stream = stream | |
| else: | |
| self._stream = _sys.stdout | |
| self._compact = bool(compact) | |
| def pprint(self, object): | |
| self._format(object, self._stream, 0, 0, {}, 0) | |
| self._stream.write("\n") | |
| def pformat(self, object): | |
| sio = _StringIO() | |
| self._format(object, sio, 0, 0, {}, 0) | |
| return sio.getvalue() | |
| def isrecursive(self, object): | |
| return self.format(object, {}, 0, 0)[2] | |
| def isreadable(self, object): | |
| s, readable, recursive = self.format(object, {}, 0, 0) | |
| return readable and not recursive | |
| def _format(self, object, stream, indent, allowance, context, level): | |
| objid = id(object) | |
| if objid in context: | |
| stream.write(_recursion(object)) | |
| self._recursive = True | |
| self._readable = False | |
| return | |
| rep = self._repr(object, context, level) | |
| max_width = self._width - indent - allowance | |
| if len(rep) > max_width: | |
| p = self._dispatch.get(type(object).__repr__, None) | |
| if p is not None: | |
| context[objid] = 1 | |
| p(self, object, stream, indent, allowance, context, level + 1) | |
| del context[objid] | |
| return | |
| elif isinstance(object, dict): | |
| context[objid] = 1 | |
| self._pprint_dict(object, stream, indent, allowance, | |
| context, level + 1) | |
| del context[objid] | |
| return | |
| stream.write(rep) | |
| _dispatch = {} | |
| def _pprint_dict(self, object, stream, indent, allowance, context, level): | |
| write = stream.write | |
| write('{') | |
| if self._indent_per_level > 1: | |
| write((self._indent_per_level - 1) * ' ') | |
| length = len(object) | |
| if length: | |
| items = sorted(object.items(), key=_safe_tuple) | |
| self._format_dict_items(items, stream, indent, allowance + 1, | |
| context, level) | |
| write('}') | |
| _dispatch[dict.__repr__] = _pprint_dict | |
| def _pprint_ordered_dict(self, object, stream, indent, allowance, context, level): | |
| if not len(object): | |
| stream.write(repr(object)) | |
| return | |
| cls = object.__class__ | |
| stream.write(cls.__name__ + '(') | |
| self._format(list(object.items()), stream, | |
| indent + len(cls.__name__) + 1, allowance + 1, | |
| context, level) | |
| stream.write(')') | |
| _dispatch[_collections.OrderedDict.__repr__] = _pprint_ordered_dict | |
| def _pprint_list(self, object, stream, indent, allowance, context, level): | |
| stream.write('[') | |
| self._format_items(object, stream, indent, allowance + 1, | |
| context, level) | |
| stream.write(']') | |
| _dispatch[list.__repr__] = _pprint_list | |
| def _pprint_tuple(self, object, stream, indent, allowance, context, level): | |
| stream.write('(') | |
| endchar = ',)' if len(object) == 1 else ')' | |
| self._format_items(object, stream, indent, allowance + len(endchar), | |
| context, level) | |
| stream.write(endchar) | |
| _dispatch[tuple.__repr__] = _pprint_tuple | |
| def _pprint_set(self, object, stream, indent, allowance, context, level): | |
| if not len(object): | |
| stream.write(repr(object)) | |
| return | |
| typ = object.__class__ | |
| if typ is set: | |
| stream.write('{') | |
| endchar = '}' | |
| else: | |
| stream.write(typ.__name__ + '({') | |
| endchar = '})' | |
| indent += len(typ.__name__) + 1 | |
| object = sorted(object, key=_safe_key) | |
| self._format_items(object, stream, indent, allowance + len(endchar), | |
| context, level) | |
| stream.write(endchar) | |
| _dispatch[set.__repr__] = _pprint_set | |
| _dispatch[frozenset.__repr__] = _pprint_set | |
| def _pprint_str(self, object, stream, indent, allowance, context, level): | |
| write = stream.write | |
| if not len(object): | |
| write(repr(object)) | |
| return | |
| chunks = [] | |
| lines = object.splitlines(True) | |
| if level == 1: | |
| indent += 1 | |
| allowance += 1 | |
| max_width1 = max_width = self._width - indent | |
| for i, line in enumerate(lines): | |
| rep = repr(line) | |
| if i == len(lines) - 1: | |
| max_width1 -= allowance | |
| if len(rep) <= max_width1: | |
| chunks.append(rep) | |
| else: | |
| # A list of alternating (non-space, space) strings | |
| parts = re.findall(r'\S*\s*', line) | |
| assert parts | |
| assert not parts[-1] | |
| parts.pop() # drop empty last part | |
| max_width2 = max_width | |
| current = '' | |
| for j, part in enumerate(parts): | |
| candidate = current + part | |
| if j == len(parts) - 1 and i == len(lines) - 1: | |
| max_width2 -= allowance | |
| if len(repr(candidate)) > max_width2: | |
| if current: | |
| chunks.append(repr(current)) | |
| current = part | |
| else: | |
| current = candidate | |
| if current: | |
| chunks.append(repr(current)) | |
| if len(chunks) == 1: | |
| write(rep) | |
| return | |
| if level == 1: | |
| write('(') | |
| for i, rep in enumerate(chunks): | |
| if i > 0: | |
| write('\n' + ' '*indent) | |
| write(rep) | |
| if level == 1: | |
| write(')') | |
| _dispatch[str.__repr__] = _pprint_str | |
| def _pprint_bytes(self, object, stream, indent, allowance, context, level): | |
| write = stream.write | |
| if len(object) <= 4: | |
| write(repr(object)) | |
| return | |
| parens = level == 1 | |
| if parens: | |
| indent += 1 | |
| allowance += 1 | |
| write('(') | |
| delim = '' | |
| for rep in _wrap_bytes_repr(object, self._width - indent, allowance): | |
| write(delim) | |
| write(rep) | |
| if not delim: | |
| delim = '\n' + ' '*indent | |
| if parens: | |
| write(')') | |
| _dispatch[bytes.__repr__] = _pprint_bytes | |
| def _pprint_bytearray(self, object, stream, indent, allowance, context, level): | |
| write = stream.write | |
| write('bytearray(') | |
| self._pprint_bytes(bytes(object), stream, indent + 10, | |
| allowance + 1, context, level + 1) | |
| write(')') | |
| _dispatch[bytearray.__repr__] = _pprint_bytearray | |
| def _pprint_mappingproxy(self, object, stream, indent, allowance, context, level): | |
| stream.write('mappingproxy(') | |
| self._format(object.copy(), stream, indent + 13, allowance + 1, | |
| context, level) | |
| stream.write(')') | |
| _dispatch[_types.MappingProxyType.__repr__] = _pprint_mappingproxy | |
| def _format_dict_items(self, items, stream, indent, allowance, context, | |
| level): | |
| write = stream.write | |
| indent += self._indent_per_level | |
| delimnl = ',\n' + ' ' * indent | |
| last_index = len(items) - 1 | |
| for i, (key, ent) in enumerate(items): | |
| last = i == last_index | |
| rep = self._repr(key, context, level) | |
| write(rep) | |
| write(': ') | |
| self._format(ent, stream, indent + len(rep) + 2, | |
| allowance if last else 1, | |
| context, level) | |
| if not last: | |
| write(delimnl) | |
| def _format_items(self, items, stream, indent, allowance, context, level): | |
| write = stream.write | |
| indent += self._indent_per_level | |
| if self._indent_per_level > 1: | |
| write((self._indent_per_level - 1) * ' ') | |
| delimnl = ',\n' + ' ' * indent | |
| delim = '' | |
| width = max_width = self._width - indent + 1 | |
| it = iter(items) | |
| try: | |
| next_ent = next(it) | |
| except StopIteration: | |
| return | |
| last = False | |
| while not last: | |
| ent = next_ent | |
| try: | |
| next_ent = next(it) | |
| except StopIteration: | |
| last = True | |
| max_width -= allowance | |
| width -= allowance | |
| if self._compact: | |
| rep = self._repr(ent, context, level) | |
| w = len(rep) + 2 | |
| if width < w: | |
| width = max_width | |
| if delim: | |
| delim = delimnl | |
| if width >= w: | |
| width -= w | |
| write(delim) | |
| delim = ', ' | |
| write(rep) | |
| continue | |
| write(delim) | |
| delim = delimnl | |
| self._format(ent, stream, indent, | |
| allowance if last else 1, | |
| context, level) | |
| def _repr(self, object, context, level): | |
| repr, readable, recursive = self.format(object, context.copy(), | |
| self._depth, level) | |
| if not readable: | |
| self._readable = False | |
| if recursive: | |
| self._recursive = True | |
| return repr | |
| def format(self, object, context, maxlevels, level): | |
| """Format object for a specific context, returning a string | |
| and flags indicating whether the representation is 'readable' | |
| and whether the object represents a recursive construct. | |
| """ | |
| return _safe_repr(object, context, maxlevels, level) | |
| def _pprint_default_dict(self, object, stream, indent, allowance, context, level): | |
| if not len(object): | |
| stream.write(repr(object)) | |
| return | |
| rdf = self._repr(object.default_factory, context, level) | |
| cls = object.__class__ | |
| indent += len(cls.__name__) + 1 | |
| stream.write('%s(%s,\n%s' % (cls.__name__, rdf, ' ' * indent)) | |
| self._pprint_dict(object, stream, indent, allowance + 1, context, level) | |
| stream.write(')') | |
| _dispatch[_collections.defaultdict.__repr__] = _pprint_default_dict | |
| def _pprint_counter(self, object, stream, indent, allowance, context, level): | |
| if not len(object): | |
| stream.write(repr(object)) | |
| return | |
| cls = object.__class__ | |
| stream.write(cls.__name__ + '({') | |
| if self._indent_per_level > 1: | |
| stream.write((self._indent_per_level - 1) * ' ') | |
| items = object.most_common() | |
| self._format_dict_items(items, stream, | |
| indent + len(cls.__name__) + 1, allowance + 2, | |
| context, level) | |
| stream.write('})') | |
| _dispatch[_collections.Counter.__repr__] = _pprint_counter | |
| def _pprint_chain_map(self, object, stream, indent, allowance, context, level): | |
| if not len(object.maps): | |
| stream.write(repr(object)) | |
| return | |
| cls = object.__class__ | |
| stream.write(cls.__name__ + '(') | |
| indent += len(cls.__name__) + 1 | |
| for i, m in enumerate(object.maps): | |
| if i == len(object.maps) - 1: | |
| self._format(m, stream, indent, allowance + 1, context, level) | |
| stream.write(')') | |
| else: | |
| self._format(m, stream, indent, 1, context, level) | |
| stream.write(',\n' + ' ' * indent) | |
| _dispatch[_collections.ChainMap.__repr__] = _pprint_chain_map | |
| def _pprint_deque(self, object, stream, indent, allowance, context, level): | |
| if not len(object): | |
| stream.write(repr(object)) | |
| return | |
| cls = object.__class__ | |
| stream.write(cls.__name__ + '(') | |
| indent += len(cls.__name__) + 1 | |
| stream.write('[') | |
| if object.maxlen is None: | |
| self._format_items(object, stream, indent, allowance + 2, | |
| context, level) | |
| stream.write('])') | |
| else: | |
| self._format_items(object, stream, indent, 2, | |
| context, level) | |
| rml = self._repr(object.maxlen, context, level) | |
| stream.write('],\n%smaxlen=%s)' % (' ' * indent, rml)) | |
| _dispatch[_collections.deque.__repr__] = _pprint_deque | |
| def _pprint_user_dict(self, object, stream, indent, allowance, context, level): | |
| self._format(object.data, stream, indent, allowance, context, level - 1) | |
| _dispatch[_collections.UserDict.__repr__] = _pprint_user_dict | |
| def _pprint_user_list(self, object, stream, indent, allowance, context, level): | |
| self._format(object.data, stream, indent, allowance, context, level - 1) | |
| _dispatch[_collections.UserList.__repr__] = _pprint_user_list | |
| def _pprint_user_string(self, object, stream, indent, allowance, context, level): | |
| self._format(object.data, stream, indent, allowance, context, level - 1) | |
| _dispatch[_collections.UserString.__repr__] = _pprint_user_string | |
| # Return triple (repr_string, isreadable, isrecursive). | |
| def _safe_repr(object, context, maxlevels, level): | |
| typ = type(object) | |
| if typ in _builtin_scalars: | |
| return repr(object), True, False | |
| r = getattr(typ, "__repr__", None) | |
| if issubclass(typ, dict) and r is dict.__repr__: | |
| if not object: | |
| return "{}", True, False | |
| objid = id(object) | |
| if maxlevels and level >= maxlevels: | |
| return "{...}", False, objid in context | |
| if objid in context: | |
| return _recursion(object), False, True | |
| context[objid] = 1 | |
| readable = True | |
| recursive = False | |
| components = [] | |
| append = components.append | |
| level += 1 | |
| saferepr = _safe_repr | |
| items = sorted(object.items(), key=_safe_tuple) | |
| for k, v in items: | |
| krepr, kreadable, krecur = saferepr(k, context, maxlevels, level) | |
| vrepr, vreadable, vrecur = saferepr(v, context, maxlevels, level) | |
| append("%s: %s" % (krepr, vrepr)) | |
| readable = readable and kreadable and vreadable | |
| if krecur or vrecur: | |
| recursive = True | |
| del context[objid] | |
| return "{%s}" % ", ".join(components), readable, recursive | |
| if (issubclass(typ, list) and r is list.__repr__) or \ | |
| (issubclass(typ, tuple) and r is tuple.__repr__): | |
| if issubclass(typ, list): | |
| if not object: | |
| return "[]", True, False | |
| format = "[%s]" | |
| elif len(object) == 1: | |
| format = "(%s,)" | |
| else: | |
| if not object: | |
| return "()", True, False | |
| format = "(%s)" | |
| objid = id(object) | |
| if maxlevels and level >= maxlevels: | |
| return format % "...", False, objid in context | |
| if objid in context: | |
| return _recursion(object), False, True | |
| context[objid] = 1 | |
| readable = True | |
| recursive = False | |
| components = [] | |
| append = components.append | |
| level += 1 | |
| for o in object: | |
| orepr, oreadable, orecur = _safe_repr(o, context, maxlevels, level) | |
| append(orepr) | |
| if not oreadable: | |
| readable = False | |
| if orecur: | |
| recursive = True | |
| del context[objid] | |
| return format % ", ".join(components), readable, recursive | |
| rep = repr(object) | |
| return rep, (rep and not rep.startswith('<')), False | |
| _builtin_scalars = frozenset({str, bytes, bytearray, int, float, complex, | |
| bool, type(None)}) | |
| def _recursion(object): | |
| return ("<Recursion on %s with id=%s>" | |
| % (type(object).__name__, id(object))) | |
| def _perfcheck(object=None): | |
| import time | |
| if object is None: | |
| object = [("string", (1, 2), [3, 4], {5: 6, 7: 8})] * 100000 | |
| p = PrettyPrinter() | |
| t1 = time.time() | |
| _safe_repr(object, {}, None, 0) | |
| t2 = time.time() | |
| p.pformat(object) | |
| t3 = time.time() | |
| print("_safe_repr:", t2 - t1) | |
| print("pformat:", t3 - t2) | |
| def _wrap_bytes_repr(object, width, allowance): | |
| current = b'' | |
| last = len(object) // 4 * 4 | |
| for i in range(0, len(object), 4): | |
| part = object[i: i+4] | |
| candidate = current + part | |
| if i == last: | |
| width -= allowance | |
| if len(repr(candidate)) > width: | |
| if current: | |
| yield repr(current) | |
| current = part | |
| else: | |
| current = candidate | |
| if current: | |
| yield repr(current) | |
| if __name__ == "__main__": | |
| _perfcheck() |