ライブラリのインストールとアンインストール

Pythonの仮想環境「venv」で必要なライブラリをインストールしたりアンインストールしたりする方法について書いていく。

pipが使えるかどうか確認

(.venv) Mac:eki-api shibatahiroshitaka$ pip3 --version
pip 20.2.3 from /Users/shibatahiroshitaka/Downloads/python/eki-api/.venv/lib/python3.8/site-packages/pip (python 3.8)

直接指定してインストール

pip install ライブラリ名で必要なライブラリをインストールできる。

(.venv) Mac:eki-api shibatahiroshitaka$ pip install requests
Collecting requests
  Using cached requests-2.32.4-py3-none-any.whl (64 kB)
Collecting idna<4,>=2.5
  Using cached idna-3.10-py3-none-any.whl (70 kB)
Collecting urllib3<3,>=1.21.1
  Using cached urllib3-2.2.3-py3-none-any.whl (126 kB)
Collecting certifi>=2017.4.17
  Downloading certifi-2025.7.14-py3-none-any.whl (162 kB)
     |████████████████████████████████| 162 kB 977 kB/s 
Collecting charset_normalizer<4,>=2
  Using cached charset_normalizer-3.4.2-py3-none-any.whl (52 kB)
Installing collected packages: idna, urllib3, certifi, charset-normalizer, requests
Successfully installed certifi-2025.7.14 charset-normalizer-3.4.2 idna-3.10 requests-2.32.4 urllib3-2.2.3

インストール済みのライブラリを確認

pip listで確認できる。

(.venv) Mac:eki-api shibatahiroshitaka$ pip list
Package            Version
------------------ ---------
certifi            2025.7.14
charset-normalizer 3.4.2
idna               3.10
pip                20.2.3
requests           2.32.4
setuptools         49.2.1
urllib3            2.2.3

.venv/lib/python3.8/site-packagesにもある。

requirements.txtに書き出す

(.venv) Mac:eki-api shibatahiroshitaka$ pip freeze > requirements.txt

全てのライブラリをアンインストール

(.venv) Mac:eki-api shibatahiroshitaka$ pip freeze | xargs pip uninstall -y
Found existing installation: certifi 2025.7.14
Uninstalling certifi-2025.7.14:
  Successfully uninstalled certifi-2025.7.14
Found existing installation: charset-normalizer 3.4.2
Uninstalling charset-normalizer-3.4.2:
  Successfully uninstalled charset-normalizer-3.4.2
Found existing installation: idna 3.10
Uninstalling idna-3.10:
  Successfully uninstalled idna-3.10
Found existing installation: requests 2.32.4
Uninstalling requests-2.32.4:
  Successfully uninstalled requests-2.32.4
Found existing installation: urllib3 2.2.3
Uninstalling urllib3-2.2.3:
  Successfully uninstalled urllib3-2.2.3

requirements.txtにまとめて指定してあるライブラリをインストール

(.venv) Mac:eki-api shibatahiroshitaka$ pip install -r requirements.txt
Collecting certifi==2025.7.14
  Using cached certifi-2025.7.14-py3-none-any.whl (162 kB)
Collecting charset-normalizer==3.4.2
  Using cached charset_normalizer-3.4.2-py3-none-any.whl (52 kB)
Collecting idna==3.10
  Using cached idna-3.10-py3-none-any.whl (70 kB)
Collecting requests==2.32.4
  Using cached requests-2.32.4-py3-none-any.whl (64 kB)
Collecting urllib3==2.2.3
  Using cached urllib3-2.2.3-py3-none-any.whl (126 kB)
Installing collected packages: certifi, charset-normalizer, idna, urllib3, requests
Successfully installed certifi-2025.7.14 charset-normalizer-3.4.2 idna-3.10 requests-2.32.4 urllib3-2.2.3