一：主要的知识点
1、说明
本文只是教程内容的一小段，因博客字数限制，故进行拆分。主教程链接：vtk教程——逐行解析官网所有Python示例-CSDN博客
2、知识点纪要
本段代码主要涉及的有①根据类名寻找示例代码
二：代码及注释
#!/usr/bin/env python3 import json import os import random import tempfile from datetime import datetime from operator import itemgetter from pathlib import Path from urllib.error import HTTPError from urllib.request import urlretrieve def get_program_parameters(): import argparse description = 'Get examples that use a particular VTK class for a given language.' epilogue = ''' The JSON file needed by this script is obtained from the gh-pages branch of the vtk-examples GitHub site. It is stored in your tempfile directory. If you change the URL to the JSON file, remember that there is a ten minute wait before you can overwrite the last downloaded file. To force the download specify -o on the command line. Here is the URL for an alternative site for testing: "https://raw.githubusercontent.com/ajpmaclean/web-test/gh-pages/src/Coverage/vtk_vtk-examples_xref.json" ''' parser = argparse.ArgumentParser(description=description, epilog=epilogue, formatter_class=argparse.RawTextHelpFormatter) # parser.add_argument('vtk_class', default="vtkFiltersSources",help='The desired VTK class.') # parser.add_argument('language', default="Python",help='The desired language, one of: CSharp, Cxx, Java, Python.') parser.add_argument('-a', '--all_values', action="store_true", help='All examples (Warning: Can be a very long list).') parser.add_argument('-n', '--number', type=int, default=5, help='The maximum number of examples.') parser.add_argument('-m', '--md', action='store_true', help='Display links in markdown inline format e.g. [label](URL).') parser.add_argument('-j', '--json_xref_url', default='https://raw.githubusercontent.com/Kitware/vtk-examples/gh-pages/src/Coverage/vtk_vtk-examples_xref.json', help='The URL for the JSON cross-reference file.') parser.add_argument('-o', '--overwrite', action="store_true", help='Force an initial download of the JSON cross-reference file.') args = parser.parse_args() return args.all_values, args.md, args.number, args.json_xref_url, args.overwrite def download_file(dl_path, dl_url, overwrite=False): """ Use the URL to get a file. :param dl_path: The path to download the file to. :param dl_url: The URL of the file. :param overwrite: If true, do a download even if the file exists. :return: The path to the file as a pathlib Path. """ file_name = dl_url.split('/')[-1] # Create necessary subdirectories in the dl_path # (if they don't exist). Path(dl_path).mkdir(parents=True, exist_ok=True) # Download if it doesn't exist in the directory overriding if overwrite is True. path = Path(dl_path, file_name) if not path.is_file() or overwrite: try: urlretrieve(dl_url, path) except HTTPError as e: raise RuntimeError(f'Failed to download {dl_url}. {e.reason}') return path def get_examples(d, vtk_class, lang, all_values=False, number=5, md_fmt=False): """ For the VTK Class and language return the total number of examples and a list of examples. :param d: The dictionary. :param vtk_class: The VTK Class e.g. vtkActor. :param lang: The language, e.g. Cxx. :param all_values: True if all examples are needed. :param number: The number of values. :param md_fmt: Use Markdown format with label and URL defined together. :return: Total number of examples and a list of examples. """ try: kv = d[vtk_class][lang].items() except KeyError: return None, None if len(kv) > number: if all_values: samples = list(kv) else: samples = random.sample(list(kv), number) else: samples = kv if md_fmt: links = [f'[{s.rsplit("/", 1)[1]}]({s})' for s in sorted(map(itemgetter(1), samples))] else: links = sorted(map(itemgetter(1), samples)) return len(links), links def get_crossref_dict(ref_dir, xref_url, overwrite=False): """ Download and return the json cross-reference file. This function ensures that the dictionary is recent. :param ref_dir: The directory where the file will be downloaded. :param xref_url: The URL for the JSON cross-reference file. :param overwrite: If true, do a download even if the file exists. :return: The dictionary cross-referencing vtk classes to examples. """ path = download_file(ref_dir, xref_url, overwrite=overwrite) if not path.is_file(): print(f'The path: {str(path)} does not exist.') return None dt = datetime.today().timestamp() - os.path.getmtime(path) # Force a new download if the time difference is > 10 minutes. if dt > 600: path = download_file(ref_dir, xref_url, overwrite=True) with open(path) as json_file: return json.load(json_file) def main(): all_values, md, number, xref_url, overwrite = get_program_parameters() vtk_class = "vtkNamedColors" language = "Python" language = language.lower() available_languages = {k.lower(): k for k in ['CSharp', 'Cxx', 'Java', 'Python', 'PythonicAPI']} available_languages.update({'cpp': 'Cxx', 'c++': 'Cxx', 'c#': 'CSharp'}) if language not in available_languages: print(f'The language: {language} is not available.') tmp = ', '.join(sorted([lang for lang in set(available_languages.values())])) print(f'Choose one of these: {tmp}.') return else: language = available_languages[language] xref_dict = get_crossref_dict(tempfile.gettempdir(), xref_url, overwrite) if xref_dict is None: print('The dictionary cross-referencing vtk classes to examples was not downloaded.') return total_number, examples = get_examples(xref_dict, vtk_class, language, all_values=all_values, number=number, md_fmt=md) if examples: if total_number <= number or all_values: print(f'VTK Class: {vtk_class}, language: {language}\n' f'Number of example(s): {total_number}.') else: print(f'VTK Class: {vtk_class}, language: {language}\n' f'Number of example(s): {total_number} with {number} random sample(s) shown.') print('\n'.join(examples)) else: print(f'No examples for the VTK Class: {vtk_class} and language: {language}') if __name__ == '__main__': main()