Use Case: Menu to Choose From

A training contains topics, possibly arranged in groups and subgroups. Topics depend on other topics, and refer to even other topics.

This is a structure that is not very transparent to the unaware. Simply showing a graph is not helpful, although it contains all information.

A customer who is interested in a training wants to see a good old catalog of topics in “book” form. Chapters containing subchapters and all that.

The information is there, and all that information can be computed.

cluster_python Python Programming cluster_python_basics Python: The Language Fundamentals cluster_python_advanced Python: More Language Features cluster_python_advanced_multithreading Multithreading cluster_python_advanced_oo Object Oriented Programming cluster_python_exercises Exercises cluster_python_exercises_legacy Exercises (Legacy) cluster_python_exercises_userdb User Database (Exercise Series) cluster_python_exercises_csv CSV and Databases cluster_python_exercises_herdt Exercises (External) cluster_python_exercises_sensors Sensors, And Data Acquisition (Exercise Series) cluster_python_misc Python: Miscellaneous Topics cluster_python_misc_ai Machine Learning, Artificial Intelligence cluster_python_misc_pandas Pandas cluster_python_swdev Python: Project/Package Management cluster_python_swdev_pytest PyTest cluster_python_drafts Python: Draft Topics cluster_python_db Databases python_python_5550_xml_etree XML: ElementTree (etree) python_basics_python_0220_for for Loops python_python_5550_xml_etree->python_basics_python_0220_for python_basics_python_0450_dictionaries More About Dictionaries python_python_5550_xml_etree->python_basics_python_0450_dictionaries python_advanced_modules Modules and Packages python_python_5550_xml_etree->python_advanced_modules python_basics_python_0130_syntax_etc Syntax etc. python_basics_python_0120_helloworld Hello World python_basics_python_0130_syntax_etc->python_basics_python_0120_helloworld python_basics_python_0225_range The range Function python_basics_python_0225_range->python_basics_python_0220_for python_basics_python_0200_sequential_types Sequential Datatypes python_basics_python_0225_range->python_basics_python_0200_sequential_types python_basics_installation Python Installation python_basics_python_0150_datatypes_overview_compound Compound Datatypes python_basics_python_0150_datatypes_overview Datatypes python_basics_python_0150_datatypes_overview_compound->python_basics_python_0150_datatypes_overview python_basics_python_0300_strings More About Strings python_basics_python_0300_strings->python_basics_python_0150_datatypes_overview python_basics_python_0250_refs_flat_deep_copy References, (Im)mutability python_basics_python_0300_strings->python_basics_python_0250_refs_flat_deep_copy python_basics_python_0300_strings->python_basics_python_0200_sequential_types python_basics_python_0460_sets More About Sets python_basics_python_0460_sets->python_basics_python_0150_datatypes_overview_compound python_basics_python_0140_variables Variables python_basics_python_0150_datatypes_overview->python_basics_python_0140_variables python_basics_python_0220_for->python_basics_python_0200_sequential_types python_basics_python_0193_while while Loops python_basics_python_0220_for->python_basics_python_0193_while python_basics_python_0139_commandline_argv Commandline Arguments (sys.argv) python_basics_python_0139_commandline_argv->python_basics_python_0130_syntax_etc python_basics_python_0125_running Running Python Programs python_basics_python_0139_commandline_argv->python_basics_python_0125_running python_basics_python_0160_boolean Boolean python_basics_python_0160_boolean->python_basics_python_0150_datatypes_overview python_basics_python_0500_files File I/O python_basics_python_0500_files->python_basics_python_0220_for python_misc_encoding Encoding python_basics_python_0500_files->python_misc_encoding python_basics_python_0270_functions Functions python_basics_python_0270_functions->python_basics_python_0150_datatypes_overview python_basics_python_0270_functions->python_basics_python_0140_variables python_basics_python_0250_refs_flat_deep_copy->python_basics_python_0150_datatypes_overview_compound python_basics_python_0250_refs_flat_deep_copy->python_basics_python_0150_datatypes_overview python_basics_python_0250_refs_flat_deep_copy->python_basics_python_0140_variables python_basics_python_1000_function_objects Function Objects python_basics_python_1000_function_objects->python_basics_python_0270_functions python_basics_python_0210_indexing_slicing Indexing and Slicing python_basics_python_0210_indexing_slicing->python_basics_python_0200_sequential_types python_basics_python_0110_blahblah Blahblah python_basics_python_0400_lists More About Lists python_basics_python_0400_lists->python_basics_python_0150_datatypes_overview_compound python_basics_python_0120_helloworld->python_basics_python_0110_blahblah python_basics_python_0320_strings_methods Miscellaneous String Methods python_basics_python_0320_strings_methods->python_basics_python_0300_strings python_basics_python_0125_running->python_basics_python_0120_helloworld python_basics_python_0200_sequential_types->python_basics_python_0150_datatypes_overview_compound python_basics_python_0450_dictionaries->python_basics_python_0150_datatypes_overview_compound python_basics_python_0450_dictionaries->python_basics_python_0220_for python_basics_python_0140_variables->python_basics_python_0130_syntax_etc python_basics_python_0310_strings_formatting String Formatting python_basics_python_0310_strings_formatting->python_basics_python_0300_strings python_basics_python_0193_while->python_basics_python_0160_boolean python_basics_python_0170_if The if Statement python_basics_python_0193_while->python_basics_python_0170_if python_basics_python_0170_if->python_basics_python_0160_boolean python_advanced_iteration_generation Iteration, Comprehensions, and Generators python_advanced_iteration_generation->python_basics_python_0220_for python_advanced_closures Closures python_advanced_closures->python_basics_python_0270_functions python_advanced_python_1010_generators_yield Iteration, Generators, And yield python_advanced_python_1010_generators_yield->python_basics_python_0225_range python_advanced_python_1010_generators_yield->python_basics_python_0220_for python_advanced_python_1010_generators_yield->python_basics_python_0270_functions python_advanced_python_1010_generators_yield->python_basics_python_0200_sequential_types python_advanced_decorators Decorators python_advanced_decorators->python_basics_python_0270_functions python_advanced_decorators->python_advanced_closures python_advanced_starargs Positional and Keyword Arguments python_advanced_decorators->python_advanced_starargs python_advanced_starargs->python_basics_python_0270_functions python_advanced_exec The exec() Function python_advanced_exec->python_basics_python_0500_files python_advanced_exec->python_basics_python_0450_dictionaries python_advanced_context_mgr Context Managers: The with Statement python_advanced_context_mgr->python_advanced_iteration_generation python_advanced_exceptions Exception Handling python_advanced_context_mgr->python_advanced_exceptions python_advanced_oo_classes_and_dicts Classes And Dictionaries python_advanced_context_mgr->python_advanced_oo_classes_and_dicts python_advanced_exceptions->python_basics_python_0270_functions python_advanced_exceptions->python_basics_python_0140_variables python_advanced_oo_inheritance Inheritance python_advanced_exceptions->python_advanced_oo_inheritance python_advanced_comprehensions Comprehensions (List, Dictionary, Set) python_advanced_comprehensions->python_basics_python_0150_datatypes_overview_compound python_advanced_multithreading_basics Multithreading (Python) python_advanced_multithreading_basics->python_advanced_oo_inheritance python_advanced_multithreading_exam_questions Multithreading: Exam Questions python_advanced_multithreading_exam_questions->python_advanced_multithreading_basics python_advanced_multithreading_mutex Race Conditions, and Mutexes python_advanced_multithreading_exam_questions->python_advanced_multithreading_mutex python_advanced_multithreading_mutex->python_advanced_multithreading_basics python_advanced_oo_abc Abstract Base Classes (abc), And Duck Typing python_advanced_oo_abc->python_advanced_oo_inheritance python_advanced_oo_inheritance->python_advanced_oo_classes_and_dicts python_advanced_oo_constructor Constructor python_advanced_oo_inheritance->python_advanced_oo_constructor python_advanced_oo_classes_and_dicts->python_basics_python_0150_datatypes_overview_compound python_advanced_oo_properties Properties python_advanced_oo_properties->python_advanced_oo_classes_and_dicts python_advanced_oo_str_repr str() And repr() python_advanced_oo_methods Methods python_advanced_oo_str_repr->python_advanced_oo_methods python_advanced_oo_namedtuple collections.namedtuple python_advanced_oo_namedtuple->python_advanced_oo_classes_and_dicts python_advanced_oo_methods->python_advanced_oo_classes_and_dicts python_advanced_oo_constructor->python_advanced_oo_classes_and_dicts python_advanced_oo_operator_overloading Operator Overloading python_advanced_oo_operator_overloading->python_advanced_oo_classes_and_dicts python_exercises_legacy_uniq_generator Exercise: Generator: uniq() python_exercises_legacy_uniq_generator->python_advanced_python_1010_generators_yield python_exercises_legacy_passwd Exercise: Parsing /etc/passwd python_exercises_legacy_uniq_generator->python_exercises_legacy_passwd python_exercises_legacy_uniq_function Exercise: Function: uniq() python_exercises_legacy_uniq_generator->python_exercises_legacy_uniq_function python_exercises_legacy_mixed_list_interactive Exercise: Mixed List (Interactive Interpreter) python_exercises_legacy_mixed_list_interactive->python_basics_python_0150_datatypes_overview_compound python_exercises_legacy_mixed_list_interactive->python_basics_python_0150_datatypes_overview python_exercises_legacy_mixed_list_interactive->python_basics_python_0160_boolean python_exercises_legacy_mixed_list_interactive->python_basics_python_0140_variables python_exercises_legacy_python_0350_exercises Exercise: String (Right-Justify) python_exercises_legacy_python_0350_exercises->python_basics_python_0300_strings python_exercises_legacy_python_0350_exercises->python_basics_python_0320_strings_methods python_exercises_legacy_python_0350_exercises->python_basics_python_0310_strings_formatting python_exercises_legacy_join_function Exercise: Functions: join() python_exercises_legacy_python_0350_exercises->python_exercises_legacy_join_function python_exercises_legacy_mixed_list_executable Exercise: Mixed List (Executable Program) python_exercises_legacy_mixed_list_executable->python_basics_python_0150_datatypes_overview_compound python_exercises_legacy_mixed_list_executable->python_basics_python_0150_datatypes_overview python_exercises_legacy_mixed_list_executable->python_basics_python_0160_boolean python_exercises_legacy_mixed_list_executable->python_basics_python_0120_helloworld python_exercises_legacy_mixed_list_executable->python_basics_python_0140_variables python_exercises_legacy_mixed_list_executable->python_exercises_legacy_mixed_list_interactive python_exercises_legacy_passwd->python_basics_python_0139_commandline_argv python_exercises_legacy_passwd->python_basics_python_0500_files python_exercises_legacy_passwd->python_basics_python_0210_indexing_slicing python_exercises_legacy_passwd->python_basics_python_0450_dictionaries python_exercises_legacy_distill Exercise: Eliminate Empty/Comment-Only Lines python_exercises_legacy_passwd->python_exercises_legacy_distill python_exercises_legacy_function_primeness Exercise: Primeness (Function) python_exercises_legacy_function_primeness->python_basics_python_0139_commandline_argv python_exercises_legacy_function_primeness->python_basics_python_0270_functions python_exercises_legacy_max_numbers_function Exercise: Determine Maximum of Two Numbers (Function) python_exercises_legacy_function_primeness->python_exercises_legacy_max_numbers_function python_exercises_legacy_uniq_function->python_basics_python_0150_datatypes_overview_compound python_exercises_legacy_uniq_function->python_basics_python_0270_functions python_exercises_legacy_uniq_function->python_exercises_legacy_function_primeness python_exercises_legacy_revert Exercise: Reverting Lines of a File python_exercises_legacy_revert->python_basics_python_0139_commandline_argv python_exercises_legacy_revert->python_basics_python_0500_files python_exercises_legacy_wc Exercise: Counting Lines, Words, Characters python_exercises_legacy_revert->python_exercises_legacy_wc python_exercises_legacy_max_numbers_function->python_basics_python_0270_functions python_exercises_legacy_max_numbers Exercise: Determine Maximum of Two Numbers python_exercises_legacy_max_numbers_function->python_exercises_legacy_max_numbers python_exercises_legacy_for_primeness Exercise: Primeness (for) python_exercises_legacy_max_numbers_function->python_exercises_legacy_for_primeness python_exercises_legacy_while_primeness Exercise: Primeness (while) python_exercises_legacy_while_primeness->python_basics_python_0139_commandline_argv python_exercises_legacy_while_primeness->python_basics_python_0193_while python_exercises_legacy_cmdline_digit Exercise: Digit to English Word python_exercises_legacy_while_primeness->python_exercises_legacy_cmdline_digit python_exercises_legacy_wc->python_basics_python_0139_commandline_argv python_exercises_legacy_wc->python_basics_python_0500_files python_exercises_legacy_wc->python_exercises_legacy_python_0350_exercises python_exercises_legacy_join_function->python_basics_python_0150_datatypes_overview_compound python_exercises_legacy_join_function->python_basics_python_0150_datatypes_overview python_exercises_legacy_join_function->python_basics_python_0270_functions python_exercises_legacy_join_function->python_exercises_legacy_uniq_function python_exercises_legacy_python_1011_generators_yield Exercise: Generator: Fibonacci python_exercises_legacy_python_1011_generators_yield->python_advanced_python_1010_generators_yield python_exercises_legacy_python_1011_generators_yield->python_exercises_legacy_uniq_generator python_exercises_legacy_distill->python_basics_python_0139_commandline_argv python_exercises_legacy_distill->python_basics_python_0500_files python_exercises_legacy_distill->python_exercises_legacy_revert python_exercises_legacy_cmdline_digit->python_basics_python_0150_datatypes_overview_compound python_exercises_legacy_cmdline_digit->python_basics_python_0150_datatypes_overview python_exercises_legacy_cmdline_digit->python_basics_python_0139_commandline_argv python_exercises_legacy_cmdline_digit->python_basics_python_0120_helloworld python_exercises_legacy_max_numbers->python_basics_python_0139_commandline_argv python_exercises_legacy_max_numbers->python_basics_python_0140_variables python_exercises_legacy_max_numbers->python_basics_python_0170_if python_exercises_legacy_max_numbers->python_exercises_legacy_mixed_list_executable python_exercises_legacy_for_primeness->python_basics_python_0225_range python_exercises_legacy_for_primeness->python_basics_python_0220_for python_exercises_legacy_for_primeness->python_exercises_legacy_while_primeness python_exercises_legacy_dict_keyerror Exercise: Dictionary: Errors? python_exercises_legacy_dict_keyerror->python_basics_python_0150_datatypes_overview_compound python_exercises_userdb_csvreader_function Exercise: Refactoring - Extract CSV Reading Into Function (csv.reader) python_exercises_userdb_csvreader_function->python_basics_python_0270_functions python_exercises_userdb_csvreader Exercise: Read CSV File (csv.reader) python_exercises_userdb_csvreader_function->python_exercises_userdb_csvreader python_exercises_userdb_mqtt_publish_csv Exercise: MQTT: Publish User Records python_exercises_userdb_user_json Exercise: Convert User Record To JSON And Back python_exercises_userdb_mqtt_publish_csv->python_exercises_userdb_user_json python_exercises_userdb_csvreader->python_basics_python_0139_commandline_argv python_misc_csv CSV Files python_exercises_userdb_csvreader->python_misc_csv python_exercises_userdb_user_class_person Exercise: Away From Raw Dictionaries python_exercises_userdb_user_class_person->python_advanced_oo_namedtuple python_exercises_userdb_userdb_module Exercise: Refactoring - Extract Both CSV Formats Into Module python_exercises_userdb_user_class_person->python_exercises_userdb_userdb_module python_exercises_userdb_user_class_person->python_exercises_userdb_user_json python_exercises_userdb_userdb_module->python_advanced_modules python_exercises_userdb_userdb_module->python_exercises_userdb_csvreader python_exercises_userdb_csvdictreader_function Exercise: Refactoring - Extract CSV Reading Into Function (csv.dictreader) python_exercises_userdb_userdb_module->python_exercises_userdb_csvdictreader_function python_exercises_userdb_csvdictreader Exercise: Read CSV File (csv.dictreader) python_exercises_userdb_csvdictreader->python_basics_python_0139_commandline_argv python_exercises_userdb_csvdictreader->python_exercises_userdb_csvreader python_exercises_userdb_csvdictreader->python_misc_csv python_exercises_userdb_user_json->python_exercises_userdb_userdb_module python_exercises_userdb_csvdictreader_function->python_basics_python_0270_functions python_exercises_userdb_csvdictreader_function->python_exercises_userdb_csvdictreader python_exercises_csv_csv_module Exercise: Read CSV File python_exercises_csv_csv_module->python_basics_python_0139_commandline_argv python_exercises_csv_csv_module->python_advanced_python_1010_generators_yield python_exercises_csv_csv_module->python_advanced_modules python_exercises_csv_csv_module->python_misc_csv python_exercises_csv_csv_db Exercise: Read CSV File, Write into Sqlite3 Database python_exercises_csv_csv_db->python_basics_python_0139_commandline_argv python_db_sqlite3 DBAPI 2: sqlite3 python_exercises_csv_csv_db->python_db_sqlite3 python_exercises_herdt_max_numbers Exercise: Determine Maximum of Two Numbers python_exercises_herdt_max_numbers->python_basics_python_0139_commandline_argv python_exercises_herdt_max_numbers->python_basics_python_0140_variables python_exercises_herdt_max_numbers->python_basics_python_0170_if python_exercises_herdt_swap Exercise: Swap Two Variables python_exercises_herdt_max_numbers->python_exercises_herdt_swap python_exercises_herdt_boolean Exercise: Boolean Expressions python_exercises_herdt_boolean->python_basics_python_0160_boolean python_exercises_herdt_username_password Exercise: Username/Password Check python_exercises_herdt_username_password->python_basics_python_0170_if python_exercises_herdt_greeting Exercise: Greeting, Depending on Time of Day python_exercises_herdt_username_password->python_exercises_herdt_greeting python_exercises_herdt_while_even_numbers Exercise: Even Numbers (while) python_exercises_herdt_while_even_numbers->python_basics_python_0139_commandline_argv python_exercises_herdt_while_even_numbers->python_basics_python_0193_while python_exercises_herdt_while_even_numbers->python_exercises_herdt_username_password python_exercises_herdt_greeting->python_basics_python_0170_if python_exercises_herdt_greeting->python_exercises_herdt_max_numbers python_exercises_herdt_swap->python_basics_python_0150_datatypes_overview python_exercises_herdt_swap->python_basics_python_0120_helloworld python_exercises_herdt_swap->python_basics_python_0140_variables python_exercises_herdt_swap->python_exercises_herdt_boolean python_exercises_sensors_sensor_const Exercise: Basic “Sensor” python_exercises_sensors_sensor_const->python_advanced_oo_methods python_exercises_sensors_project_setup Project Setup python_exercises_sensors_sensor_const->python_exercises_sensors_project_setup python_exercises_sensors_project_setup->python_exercises_sensors_sensor_const python_misc_import The import Statement (incomplete) python_misc_import->python_advanced_modules python_misc_csv->python_basics_python_0150_datatypes_overview_compound python_misc_csv->python_basics_python_0220_for python_misc_csv->python_basics_python_0500_files python_misc_mqtt MQTT python_swdev_venv Virtual Environments python_misc_mqtt->python_swdev_venv python_misc_vscode Visual Studio Code for Python Programming python_misc_encoding->python_basics_python_0150_datatypes_overview python_misc_encoding->python_basics_python_0320_strings_methods python_misc_ai_linear_regression Linear Regression python_misc_ai_machine_learning_intro Machine Learning: Concepts and Terminology python_misc_ai_linear_regression->python_misc_ai_machine_learning_intro python_misc_ai_linear_regression->python_swdev_venv python_misc_ai_k_means K-Means python_misc_ai_k_means->python_misc_ai_linear_regression python_misc_ai_k_means->python_misc_ai_machine_learning_intro python_misc_ai_k_means->python_swdev_venv python_misc_pandas_loc Pandas: Selecting Rows (And Columns) With loc[] python_misc_pandas_loc->python_basics_python_0210_indexing_slicing python_misc_pandas_iloc Pandas: Selecting Rows (And Columns) With iloc[] python_misc_pandas_loc->python_misc_pandas_iloc python_misc_pandas_basics Pandas: Basics (DataFrame And Series) python_misc_pandas_loc->python_misc_pandas_basics python_misc_pandas_indexes Pandas: Indexes python_misc_pandas_loc->python_misc_pandas_indexes python_misc_pandas_iloc->python_basics_python_0210_indexing_slicing python_misc_pandas_iloc->python_misc_pandas_basics python_misc_pandas_iloc->python_misc_pandas_indexes python_misc_pandas_filters Pandas: Filters python_misc_pandas_filters->python_misc_pandas_basics python_misc_pandas_filters->python_misc_pandas_indexes python_misc_pandas_add_rows Pandas: Adding Rows python_misc_pandas_mod_col Pandas: Adding/Modifying Columns python_misc_pandas_add_rows->python_misc_pandas_mod_col python_misc_pandas_indexes->python_misc_pandas_loc python_misc_pandas_indexes->python_misc_pandas_iloc python_misc_pandas_indexes->python_misc_pandas_basics python_misc_pandas_mod_col->python_misc_pandas_basics python_swdev_pip Python Package Index python_swdev_pip->python_misc_import python_swdev_venv->python_misc_import python_swdev_venv->python_swdev_pip python_swdev_unittest The unittest Module python_swdev_unittest->python_advanced_modules python_swdev_unittest->python_advanced_oo_inheritance python_swdev_pytest_intro pytest Introduction, By Example python_swdev_pytest_intro->python_advanced_modules python_drafts_argparse Commandline Parsing with argparse python_drafts_argparse->python_basics_python_0139_commandline_argv python_drafts_matplotlib Matplotlib python_drafts_matplotlib->python_swdev_pip python_drafts_matplotlib->python_swdev_venv python_drafts_setuptools Package Installation (setuptools) python_drafts_setuptools->python_swdev_pip python_drafts_setuptools->python_swdev_venv python_drafts_asyncio asyncio python_db_dbapi2 DBAPI 2 python_db_sqlite3->python_db_dbapi2 python_db_dbapi2->python_basics_python_0220_for python_db_dbapi2->python_advanced_python_1010_generators_yield python_db_dbapi2->python_advanced_modules python_db_postgres DBAPI 2: PostgreSQL python_db_postgres->python_db_dbapi2