pretty_data.py

def pretty_data(d):
    return '\n'.join(data_lines(d))


def data_lines(d, prefix='', last=True, add_bookends=True):
    def ground(d):
        return isinstance(d, (str, float, int)) or ground_list(d) or ground_dict(d)

    def ground_list(d):
        return isinstance(d, list) and len(d) < 6 and all([isinstance(el, (str, float, int)) for el in d])

    def ground_dict(d):
        return isinstance(d, dict) and len(d) == 0

    def format_ground(el):
        if isinstance(el, int):
            return str(el)
        if isinstance(el, float):
            return '{:.2f}'.format(el)
        if isinstance(el, str):
            return "'{}'".format(el)
        if ground_list(el):
            return '[{}]'.format(', '.join(map(format_ground, el)))
        if ground_dict(el):
            return '{}'
        assert False, 'expected {} to be ground type'.format(el)

    if ground(d):
        return ['{}{}'.format(prefix, format_ground(d))]

    if isinstance(d, list):
        result = ['{}['.format(prefix)] if add_bookends else []
        child_prefix = prefix + 2*' '# if add_bookends else prefix
        last_i = len(d) - 1
        for idx, el in enumerate(d):
            last_child = idx == last_i
            result.extend(data_lines(el, child_prefix, last=last_child))
        postfix = '' if last else ','
        if add_bookends:
            result.append('{}]{}'.format(prefix, postfix))
        return result
    if isinstance(d, dict):
        result = ['{}{{'.format(prefix)] if add_bookends else []
        key_prefix = prefix + 2 * ' '
        last_i = len(d) - 1
        for idx, (k, v) in enumerate(d.items()):
            last_child = idx == last_i
            if ground(v):
                result.append('{}{}: {},'.format(key_prefix, format_ground(k), format_ground(v)))
            else:
                if isinstance(v, dict):
                    result.append('{}{}: {{'.format(key_prefix, format_ground(k)))
                elif isinstance(v, list):
                    result.append('{}{}: ['.format(key_prefix, format_ground(k)))
                val_prefix = key_prefix + 2 * ' ' if add_bookends else key_prefix
                result.extend(data_lines(v, val_prefix, last=last_child, add_bookends=False))
                postfix = '' if last_child else ','
                if isinstance(v, dict):
                    result.append('{}}}{}'.format(key_prefix, postfix))
                elif isinstance(v, list):
                    result.append('{}]{}'.format(key_prefix, postfix))
        postfix = '' if last else ','
        if add_bookends:
            result.append('{}}}{}'.format(prefix, postfix))
        return result