Why does adding new column in pandas

[PyCharm] Unable to see code coverage button: https://www.reddit.com/r/Python/comments/5zacgi/pycharm_unable_to_see_code_coverage_button/

First Python Notebook: https://www.reddit.com/r/Python/comments/5zajve/first_python_notebook/

undecorated 0.2.0 - Undecorate python functions or methods: https://www.reddit.com/r/Python/comments/5zai4j/undecorated_020_undecorate_python_functions_or/

On Pi Day learn and use the Monte Carlo method to estimate Pi method in 30 minutes with Python: https://www.reddit.com/r/Python/comments/5zb72h/on_pi_day_learn_and_use_the_monte_carlo_method_to/

Parallel Python: http://www.parallelpython.com/

Machine Learning with Python - Part 2: https://www.reddit.com/r/Python/comments/5zaskv/machine_learning_with_python_part_2/

A chatbot that connects to your favorite chat service and brings your tools and fun into the conversation: https://www.reddit.com/r/Python/comments/5zba3p/a_chatbot_that_connects_to_your_favorite_chat/

What is wrong with this poll on the most elegant programming language?: https://www.reddit.com/r/Python/comments/5zbph7/what_is_wrong_with_this_poll_on_the_most_elegant/

Running several ApplicationSessions non-blockingly using autbahn.asyncio.wamp: http://stackoverflow.com/questions/42535610/running-several-applicationsessions-non-blockingly-using-autbahn-asyncio-wamp

doit - a task management

Parallel Python: https://www.reddit.com/r/Python/comments/5zbxs4/parallel_python/

Machine Learning in Python: free curriculum: https://www.springboard.com/learning-paths/machine-learning-python/

Very new to Python....just a thought on a couple of things to help me learn.: https://www.reddit.com/r/Python/comments/5zc3eo/very_new_to_pythonjust_a_thought_on_a_couple_of/

It'sPiDay! Use the pidigits Python package to generate the decimal expansion of Pi: https://www.reddit.com/r/Python/comments/5zc8cb/itspiday_use_the_pidigits_python_package_to/

Continually updated Data Science Notebooks: Deep learning (TensorFlow, Theano, Caffe, Keras), Spark, Hadoop MapReduce, Kaggle, scikit-learn, matplotlib, pandas, NumPy, AWS, Python essentials, and various command lines: https://www.reddit.com/r/Python/comments/5zbzwe/continually_updated_data_science_notebooks_deep/

What's everyone working on this week?: https://www.reddit.com/r/Python/comments/5zcavk/whats_everyone_working_on_this_week/

Python library with tools to download, label and sort music files.: https://www.reddit.com/r/Python/comments/5zcf11/python_library_with_tools_to_download_label_and/

Determine all files read into and written from an ipython notebook: http://stackoverflow.com/questions/42288163/determine-all-files-read-into-and-written-from-an-ipython-notebook

Using the ELK Stack and Python in Penetration Testing Workflow: https://www.reddit.com/r/Python/comments/5zcva8/using_the_elk_stack_and_python_in_penetration/