Checking whether the pip is installed?

问题

I am using Python 2.7.12 and I want to check whether the pip is installed or not. For this, in command line of Python application I wrote pip list and pressed enter. However, I get an error like:

File"stdin",line 1

pip list

Syntax Error: invalid syntax

So, how can I solve this issue and get the list of modules as an output?

Thanks

回答1:

Use command line and not python.
TLDR; On Windows, do: python -m pip --version

Details:

On Windows, ~> (open windows terminal)
Start (or Windows Key) > type "cmd" Press Enter
You should see a screen that looks like this
To check to see if pip is installed.

python -m pip --version

if pip is installed, go ahead and use it. for example:

Z:\>python -m pip install selenium

if not installed, install pip, and you may need to
add its path to the environment variables. (basic - windows)
add path to environment variables (basic+advanced)

if python is NOT installed you will get a result similar to the one below

Install python. add its path to environment variables.

回答2:

$ which pip

or

 $ pip -V 

execute this command into your terminal. It should display the location of executable file eg. /usr/local/bin/pip and the second command will display the version if the pip is installed correctly.

回答3:

If you are on a linux machine running Python 2 you can run this commands:

1st make sure python 2 is installed:

python2 --version

2nd check to see if pip is installed:

pip --version

If you are running Python 3 you can run this command:

1st make sure python 3 is installed:

python3 --version

2nd check to see if pip3 is installed:

pip3 --version

If you do not have pip installed you can run these commands to install pip (it is recommended you install pip for Python 2 and Python 3):

Install pip for Python 2:

sudo apt install python-pip

Then verify if it is installed correctly:

pip --version

Install pip for Python 3:

sudo apt install python3-pip

Then verify if it is installed correctly:

pip3 --version

For more info see: https://itsfoss.com/install-pip-ubuntu/

回答4:

You need to run pip list in bash not in python.

pip list
DEPRECATION: Python 2.6 is no longer supported by the Python core team, please upgrade your Python. A future version of pip will drop support for Python 2.6
argparse (1.4.0)
Beaker (1.3.1)
cas (0.15)
cups (1.0)
cupshelpers (1.0)
decorator (3.0.1)
distribute (0.6.10)
---and other modules

回答5:

pip list is a shell command. You should run it in your shell (bash/cmd), rather than invoke it from python interpreter.

If you want to do it from a python script, you would need to import pip module first:

import pip
pip.get_installed_distributions()

However, if you want to just check if pip exists locally, and you are running Linux, I would suggest that you use bash's which command:

which pip

It should show you whether the command can be found in bash's PATH/aliases, and if it does, what does it actually execute.

If you really need to do it from a python script, you can always put the import statement into a try...except block:

try:
    import pip
except ImportError:
    print("Pip not present.")

回答6:

In CMD, type:

pip freeze

And it will show you a list of all the modules installed including the version number.

Output:

aiohttp==1.1.4
async-timeout==1.1.0
cx-Freeze==4.3.4
Django==1.9.2
django-allauth==0.24.1
django-cors-headers==1.2.2
django-crispy-forms==1.6.0
django-robots==2.0
djangorestframework==3.3.2
easygui==0.98.0
future==0.16.0
httpie==0.9.6
matplotlib==1.5.3
multidict==2.1.2
numpy==1.11.2
oauthlib==1.0.3
pandas==0.19.1
pefile==2016.3.28
pygame==1.9.2b1
Pygments==2.1.3
PyInstaller==3.2
pyparsing==2.1.10
pypiwin32==219
PyQt5==5.7
pytz==2016.7
requests==2.9.1
requests-oauthlib==0.6
six==1.10.0
sympy==1.0
virtualenv==15.0.3
xlrd==1.0.0
yarl==0.7.0

来源：https://stackoverflow.com/questions/40868345/checking-whether-the-pip-is-installed