Nice job! After tackling ten separate tasks, you’ve successfully completed this coding challenge. You now have a working clone of the Unix wc command, which you implemented in Python. How did it go for you? Share your solution in the comments sections!
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Sample Solution
You can expand the collapsible section below to reveal the complete source code of a sample solution for this coding challenge:
Python
src/wordcount.py
import sys
from argparse import ArgumentParser, Namespace
from dataclasses import dataclass
from enum import IntFlag, auto
from functools import cached_property
from pathlib import Path
from typing import NamedTuple
class SelectedCounts(IntFlag):
NONE = 0
LINES = auto()
WORDS = auto()
CHARS = auto()
BYTES = auto()
DEFAULT = LINES | WORDS | BYTES
class Arguments(Namespace):
@cached_property
def selected_counts(self):
selected = self.lines | self.words | self.chars | self.bytes
return selected or SelectedCounts.DEFAULT
class Counts(NamedTuple):
lines: int = 0
words: int = 0
chars: int = 0
bytes: int = 0
def max_digits(self, selected_counts):
return len(str(max(self.numbers(selected_counts))))
def __add__(self, other):
return Counts(
lines=self.lines + other.lines,
words=self.words + other.words,
chars=self.chars + other.chars,
bytes=self.bytes + other.bytes,
)
def as_string(self, max_digits, selected_counts):
return " ".join(
f"{number:>{max_digits}}"
for number in self.numbers(selected_counts)
)
def numbers(self, selected_counts):
return [
getattr(self, flag.name.lower())
for flag in SelectedCounts
if flag & selected_counts
]
@dataclass(frozen=True)
class FileInfo:
path: Path
counts: Counts
@classmethod
def from_path(cls, path):
if path.name == "-":
raw_text = sys.stdin.buffer.read()
elif path.is_file():
raw_text = path.read_bytes()
else:
return cls(path, Counts())
text = raw_text.decode("utf-8")
return cls(
path,
Counts(
lines=text.count("\n"),
words=len(text.split()),
chars=len(text),
bytes=len(raw_text),
),
)
def main():
args = parse_args()
if len(args.paths) > 0:
file_infos = [FileInfo.from_path(path) for path in args.paths]
else:
file_infos = [FileInfo.from_path(Path("-"))]
display(file_infos, args.selected_counts)
def parse_args():
parser = ArgumentParser()
parser.add_argument("paths", nargs="*", type=Path)
for flag in SelectedCounts:
parser.add_argument(
f"--{flag.name.lower()}",
action="store_const",
const=flag,
default=SelectedCounts.NONE,
)
return parser.parse_args(namespace=Arguments())
def display(file_infos, selected_counts):
total_counts = sum((info.counts for info in file_infos), Counts())
max_digits = total_counts.max_digits(selected_counts)
for info in file_infos:
line = info.counts.as_string(max_digits, selected_counts)
if info.path == Path("-"):
print(line)
elif not info.path.exists():
print(line, info.path, "(no such file or directory)")
elif info.path.is_dir():
print(line, f"{info.path}/ (is a directory)")
else:
print(line, info.path)
if len(file_infos) > 1:
print(total_counts.as_string(max_digits, selected_counts), "total")
