python - 从命令行漂亮地打印 Python 字典

Question

我可以轻松地从命令行打印 JSON:

$ echo '{"hello": "world"}' |python -mjson.tool
{
    "hello": "world"
}

但是它不适用于 Python 字典(显然):

$ echo "{'hello': None}" |python -mjson.tool
Expecting property name: line 1 column 1 (char 1)

是否有一些类似于 json.tool 的内置类可以用来漂亮地打印 Python 数据结构？

Answer 1

如果您确实想要命令行解决方案，您可以使用 pprint library在命令行中:

$ echo "{'python': {'hello': [1,2,3,4,42,81,113,256], 'world': ['spam', 'ham', 'eggs', 'bacon', 'eric', 'idle']}}" \
    | python -c 'import sys; from pprint import pprint as pp; pp(eval(sys.stdin.read()))'
{'python': {'hello': [1, 2, 3, 4, 42, 81, 113, 256],
            'world': ['spam', 'ham', 'eggs', 'bacon', 'eric', 'idle']}}

这很容易被包装在模块中；将此命名为 pprint_tool.py:

import sys
import ast
from pprint import pprint


def main():
    if len(sys.argv) == 1:
        infile = sys.stdin
        outfile = sys.stdout
    elif len(sys.argv) == 2:
        infile = open(sys.argv[1], 'rb')
        outfile = sys.stdout
    elif len(sys.argv) == 3:
        infile = open(sys.argv[1], 'rb')
        outfile = open(sys.argv[2], 'wb')
    else:
        raise SystemExit(sys.argv[0] + " [infile [outfile]]")
    with infile:
        try:
            obj = ast.literal_eval(infile.read())
        except ValueError as e:
            raise SystemExit(e)
    with outfile:
        pprint(obj, outfile)


if __name__ == '__main__':
    main()

这将像 json.tool 模块一样工作:

echo "..." | python -m pprint_tool