Short - Yes! 

The lock file tells pipenv exactly which version of each dependency needs to be installed. You will have consistency across all machines.

// update: [Same question on github][1]


  [1]: https://github.com/pypa/pipenv/issues/598

I&#39;m using axios to check if an alias has not already been used by another in the database.

**Problem**:
The ajax call doesn&#39;t wait for the server response to execute the remaining code.

The code looks like :

    export default {
        data () {
            return {
                id: null,
                alias: null,
                valid: true,
            }
        },

        methods: {
            // triggered by the save button
            save () {
                this.valid = true;
                console.log(&#39;before checking&#39;);

                this.checkUniqueness();
                // other validations here

                if (this.valid) {
                    console.log(&#39;3. checked valid, can save now&#39;);
                    // save now
                }
            },

            checkUniqueness () {
                axios.get(&#39;/api/unique/alias&#39;, {
                    params: {
                        id: this.id,
                        alias: this.alias,
                    }
                })
                    .then((response) =&gt; {
                        console.log(&#39;2. server response:&#39; + response.data.unique)
                        this.valid = response.data.unique;
                    });
            },

        },
    }

The console shows the following result:

```
1. before checking
3. checked valid, can save now
2. server response:false
```

I cannot move the code of the `save()` method into `.then` because I do other validations on the input data such as alpha-numeric characters, minimum of characters...

I was able to delay the 3rd part (`if (this.valid) {`) using set `setTimeout` but it&#39;s not the best solution. what if the server takes more or less than the defined waiting time..

**Question** Is there a way to make this call sequential (1, 2, 3) instead of (1, 3, 2)?

How to make axios synchronous

What do these three dots mean exactly, and why do I need them?

    export function leadReducer(state: Lead[]= [], action: Action {
        switch(action.type){
            case ADD_LEAD:
                return [...state, action.payload];
            case REMOVE_LEAD:
                return state.filter(lead =&gt; lead.id !== action.payload.id )
    }
    }

Angular what&#39;s the meaning of these three dots in @NGRX

When two developers are working on a project with different operating systems, the `Pipfile.lock` is different (especially the part inside `host-environment-markers`).

[For PHP, most people recommend to commit `composer.lock`](https://stackoverflow.com/questions/12896780/should-composer-lock-be-committed-to-version-control) file.

Do we have to do the same for Python?

Git - Should Pipfile.lock be committed to version control?

When two developers are working on a project with different operating systems, the <code>Pipfile.lock</code> is different (especially the part inside <code>host-environment-markers</code>).
<a href="https://stackoverflow.com/questions/12896780/should-composer-lock-be-committed-to-version-control" target="_blank" rel="noopener noreferrer">For PHP, most people recommend to commit <code>composer.lock</code></a> file.
Do we have to do the same for Python?

My pip version was off -- every pip command was saying:


    You are using pip version 6.0.8, however version 8.1.1 is available.
    You should consider upgrading via the &#39;pip install --upgrade pip&#39; command.

And I didn&#39;t like the answers given here: https://stackoverflow.com/questions/36410756/how-can-i-get-rid-of-this-warning-to-upgrade-from-pip because they all want to get `pip` out of sync with the RH version.

So I tried a clean system install with this VagrantFile:

    Vagrant.configure(&quot;2&quot;) do |config|
    
      config.ssh.username   = &#39;root&#39;
      config.ssh.password   = &#39;vagrant&#39;
      config.ssh.insert_key = &#39;true&#39;
    
      config.vm.box = &quot;bento/centos-7.3&quot;
    
      config.vm.provider &quot;virtualbox&quot; do |vb|
        vb.cpus   = &quot;4&quot;
        vb.memory = &quot;2048&quot;
      end
    
      config.vm.synced_folder &quot;..&quot;, &quot;/vagrant&quot;
    
      config.vm.network &quot;public_network&quot;, bridge: &quot;eth0&quot;, ip: &quot;192.168.1.31&quot;
    
      config.vm.provision &quot;shell&quot;, inline: &lt;&lt;-SHELL
        set -x
    
        # Install pip
        yum install -y epel-release
        yum install -y python-pip
        pip freeze   # See if pip prints version warning on fresh OS install.
    
      SHELL
    
    end

But then I got:

    ==&gt; default: ++ pip freeze
    ==&gt; default: You are using pip version 8.1.2, however version 9.0.1 is available.
    ==&gt; default: You should consider upgrading via the &#39;pip install --upgrade pip&#39; command.

So it seems that I&#39;m using the wrong commands to install `pip`. What are correct commands to use?

How to suppress pip upgrade warning?

My question is simple, **what is the validation data** passed to model.fit in a Sequential model **used for**?

And, does it affect how the model is trained (normally a validation set is used, for example, to choose hyper-parameters in a model, but I think this does not happen here)?

I am talking about the validation set that can be passed like this:

    # Create model
    model = Sequential()
    # Add layers
    model.add(...)
    
    # Train model (use 10% of training set as validation set)
    history = model.fit(X_train, Y_train, validation_split=0.1)

    # Train model (use validation data as validation set)
    history = model.fit(X_train, Y_train, validation_data=(X_test, Y_test))

I investigated a bit, and I saw that `keras.models.Sequential.fit` calls `keras.models.training.fit`, which creates variables like `val_acc`and `val_loss` (which can be accessed from Callbacks). `keras.models.training.fit` also calls `keras.models.training._fit_loop`, which adds the validation data to the `callbacks.validation_data`, and also calls `keras.models.training._test_loop`, which will loop the validation data in batches on the `self.test_function` of the model. The result of this function is used to fill the values of the logs, which are the values accessible from the callbacks.

After seeing all this, I feel that the validation set passed to `model.fit` is not used to validate anything during training, and its only use is to get feedback on how the trained model will perform in every epoch for a completely independent set. Therefore, it would be okey to use the same validation and test set, right?

Could anyone confirm if the validation set in model.fit has any other goal besides being read from the callbacks?


What is validation data used for in a Keras Sequential model?

I&#39;m new to Python (and to programming as well) and, although well documented, I cannot understand what exactly means the -m directive (precisely in the creation of a virtual environment: `python3 -m venv my_env`. 

As far as I can read from the documentation, it stands for &quot;run library module as a script&quot;: it is in fact this concept that I cannot figure out and what is the difference in running the command without the `-m`.

Moreover, it this a characteristic of Python 3?

What does it mean to &quot;run library module as a script&quot; with the &quot;-m&quot; option?

It seems that `Pipfile` / `Pipfile.lock` are intended to be replacements for `requirements.txt`, in the context of Python packaging. There isn&#39;t much documentation out there on how these actually work, however. I found an evolving description of pipfile on the PyPi section of the Python website [here](https://pypi.python.org/pypi/pipfile/0.0.2) but it&#39;s pretty messy and doesn&#39;t explain the semantics of the different sections of the file.

Any pointers on how to understand these files?

How are Pipfile and Pipfile.lock used?

Over a period of time, I have loaded a number of packages into the Anaconda I have been using. Now I am not able to keep track of it. How do we get a list of all packages loaded in Anaconda (Windows 10)? What is the command?

Get the list of packages installed in Anaconda

I&#39;m new to Python development and attempting to use pipenv. I ran the command `pip install pipenv`, which ran successfully:

    ...
    Successfully built pipenv pathlib shutilwhich pythonz-bd virtualenv-clone
    Installing collected packages: virtualenv, pathlib, shutilwhich, backports.shutil-get-terminal-size, pythonz-bd, virtualenv-clone, pew, first, six, click, pip-tools, certifi, chardet, idna, urllib3, requests, pipenv
    ...

However, when I run the command `pipenv install` in a fresh root project directory I receive the following message: `-bash: pipenv: command not found`. I suspect that I might need to modify my .bashrc, but I&#39;m unclear about what to add to the file or if modification is even necessary.


Pipenv: Command Not Found

I am using the latest version of Anaconda3. I just installed it and I am trying to download some packages. I am using the Anaconda Prompt. While trying to use pip to do anything (including upgrading existing packages) I get the following traceback.

        Exception:
    Traceback (most recent call last):
      File &quot;C:\Users\csprock\Anaconda3\lib\site-packages\pip\basecommand.py&quot;, line 215, in main
        status = self.run(options, args)
      File &quot;C:\Users\csprock\Anaconda3\lib\site-packages\pip\commands\install.py&quot;, line 335, in run
        wb.build(autobuilding=True)
      File &quot;C:\Users\csprock\Anaconda3\lib\site-packages\pip\wheel.py&quot;, line 749, in build
        self.requirement_set.prepare_files(self.finder)
      File &quot;C:\Users\csprock\Anaconda3\lib\site-packages\pip\req\req_set.py&quot;, line 380, in prepare_files
        ignore_dependencies=self.ignore_dependencies))
      File &quot;C:\Users\csprock\Anaconda3\lib\site-packages\pip\req\req_set.py&quot;, line 487, in _prepare_file
        req_to_install, finder)
      File &quot;C:\Users\csprock\Anaconda3\lib\site-packages\pip\req\req_set.py&quot;, line 428, in _check_skip_installed
        req_to_install, upgrade_allowed)
      File &quot;C:\Users\csprock\Anaconda3\lib\site-packages\pip\index.py&quot;, line 465, in find_requirement
        all_candidates = self.find_all_candidates(req.name)
      File &quot;C:\Users\csprock\Anaconda3\lib\site-packages\pip\index.py&quot;, line 423, in find_all_candidates
        for page in self._get_pages(url_locations, project_name):
      File &quot;C:\Users\csprock\Anaconda3\lib\site-packages\pip\index.py&quot;, line 568, in _get_pages
        page = self._get_page(location)
      File &quot;C:\Users\csprock\Anaconda3\lib\site-packages\pip\index.py&quot;, line 683, in _get_page
        return HTMLPage.get_page(link, session=self.session)
      File &quot;C:\Users\csprock\Anaconda3\lib\site-packages\pip\index.py&quot;, line 811, in get_page
        inst = cls(resp.content, resp.url, resp.headers)
      File &quot;C:\Users\csprock\Anaconda3\lib\site-packages\pip\index.py&quot;, line 731, in __init__
        namespaceHTMLElements=False,
    TypeError: parse() got an unexpected keyword argument &#39;transport_encoding&#39;

Any ideas? (this problem only started after I installed tensorflow) Thanks. 

pip throws TypeError: parse() got an unexpected keyword argument &#39;transport_encoding&#39; when trying to install new packages

I see more and more commands like this:

    $ pip install &quot;splinter[django]&quot;

What do these square brackets do?

What do square brackets mean in pip install?

Im installing pipenv in my docker:

    RUN pip install pipenv
    RUN cd /my/app/path/ &amp;&amp; pipenv install
    RUN cd /my/app/path/ &amp;&amp; pipenv shell

Im getting the error:

	Traceback (most recent call last):
	  File &quot;/usr/local/bin/pipenv&quot;, line 11, in &lt;module&gt;
		sys.exit(cli())
	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py&quot;, line 722, in __call__
		return self.main(*args, **kwargs)
	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py&quot;, line 697, in main
		rv = self.invoke(ctx)
	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py&quot;, line 1066, in invoke
		return _process_result(sub_ctx.command.invoke(sub_ctx))
	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py&quot;, line 895, in invoke
		return ctx.invoke(self.callback, **ctx.params)
	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py&quot;, line 535, in invoke
		return callback(*args, **kwargs)
	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/cli.py&quot;, line 2057, in shell
		do_shell(three=three, python=python, fancy=fancy, shell_args=shell_args)
	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/cli.py&quot;, line 1952, in do_shell
		shell = os.path.abspath(PIPENV_SHELL)
	  File &quot;/usr/lib/python2.7/posixpath.py&quot;, line 360, in abspath
		if not isabs(path):
	  File &quot;/usr/lib/python2.7/posixpath.py&quot;, line 54, in isabs
		return s.startswith(&#39;/&#39;)
	AttributeError: &#39;NoneType&#39; object has no attribute &#39;startswith&#39;

If I run

    RUN cd /my/app/path/ &amp;&amp; pipenv install --system 

instead, im getting another error:

	build	30-Sep-2017 16:50:45	Step 5/9 : RUN cd /my/app/path &amp;&amp;     pipenv install --system
	build	30-Sep-2017 16:50:45	 ---&gt; Running in cffd31633074
	build	30-Sep-2017 16:50:46	[91mPipfile.lock not found, creating&#226;€&#166;
	build	30-Sep-2017 16:50:46	[0m[91mLocking [dev-packages] dependencies&#226;€&#166;
	build	30-Sep-2017 16:50:46	[0m[91mLocking [packages] dependencies&#226;€&#166;
	build	30-Sep-2017 16:50:49	[0m[91mCRITICAL:pip.utils:Error [Errno 2] No such file or directory while executing command python setup.py egg_info
	build	30-Sep-2017 16:50:49	[0m[91mTraceback (most recent call last):
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/bin/pipenv&quot;, line 11, in &lt;module&gt;
	build	30-Sep-2017 16:50:49	    sys.exit(cli())
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py&quot;, line 722, in __call__
	build	30-Sep-2017 16:50:49	[0m[91m    return self.main(*args, **kwargs)
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py&quot;, line 697, in main
	build	30-Sep-2017 16:50:49	[0m[91m    rv = self.invoke(ctx)
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py&quot;, line 1066, in invoke
	build	30-Sep-2017 16:50:49	[0m[91m    return _process_result(sub_ctx.command.invoke(sub_ctx))
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py&quot;, line 895, in invoke
	build	30-Sep-2017 16:50:49	[0m[91m    return ctx.invoke(self.callback, **ctx.params)
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py&quot;, line 535, in invoke
	build	30-Sep-2017 16:50:49	    return callback(*args, **kwargs)
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/cli.py&quot;, line 1782, in install
	build	30-Sep-2017 16:50:49	[0m[91m    do_init(dev=dev, allow_global=system, ignore_pipfile=ignore_pipfile, system=system, skip_lock=skip_lock, verbose=verbose, concurrent=concurrent, deploy=deploy)
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/cli.py&quot;, line 1290, in do_init
	build	30-Sep-2017 16:50:49	[0m[91m    do_lock(system=system)
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/cli.py&quot;, line 1080, in do_lock
	build	30-Sep-2017 16:50:49	[0m[91m    pre=pre
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/utils.py&quot;, line 421, in resolve_deps
	build	30-Sep-2017 16:50:49	[0m[91m    resolved_tree.update(resolver.resolve())
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/patched/piptools/resolver.py&quot;, line 101, in resolve
	build	30-Sep-2017 16:50:49	[0m[91m    has_changed, best_matches = self._resolve_one_round()
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/patched/piptools/resolver.py&quot;, line 199, in _resolve_one_round
	build	30-Sep-2017 16:50:49	[0m[91m    for dep in self._iter_dependencies(best_match):
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/patched/piptools/resolver.py&quot;, line 293, in _iter_dependencies
	build	30-Sep-2017 16:50:49	    dependencies = self.repository.get_dependencies(ireq)
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/patched/piptools/repositories/pypi.py&quot;, line 171, in get_dependencies
	build	30-Sep-2017 16:50:49	    result = reqset._prepare_file(self.finder, ireq)
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/patched/pip/req/req_set.py&quot;, line 639, in _prepare_file
	build	30-Sep-2017 16:50:49	[0m[91m    abstract_dist.prep_for_dist()
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/patched/pip/req/req_set.py&quot;, line 134, in prep_for_dist
	build	30-Sep-2017 16:50:49	[0m[91m    self.req_to_install.run_egg_info()
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/patched/pip/req/req_install.py&quot;, line 438, in run_egg_info
	build	30-Sep-2017 16:50:49	[0m[91m    command_desc=&#39;python setup.py egg_info&#39;)
	build	30-Sep-2017 16:50:49	  File &quot;/usr/local/lib/python2.7/dist-packages/pipenv/patched/pip/utils/__init__.py&quot;, line 667, in call_subprocess
	build	30-Sep-2017 16:50:49	[0m[91m    cwd=cwd, env=env)
	build	30-Sep-2017 16:50:49	  File &quot;/usr/lib/python2.7/subprocess.py&quot;, line 711, in __init__
	build	30-Sep-2017 16:50:49	[0m[91m    errread, errwrite)
	build	30-Sep-2017 16:50:49	  File &quot;/usr/lib/python2.7/subprocess.py&quot;, line 1343, in _execute_child
	build	30-Sep-2017 16:50:49	[0m[91m    raise child_exception
	build	30-Sep-2017 16:50:49	OSError: [Errno 2] No such file or directory
	error	30-Sep-2017 16:50:49	The command &#39;/bin/sh -c cd /opt/supercrunch/function-service/lib &amp;&amp;     pipenv install --system&#39; returned a non-zero code: 1
	build	30-Sep-2017 16:50:49	[0mSending build context to Docker daemon 40.96 kB

But when I instead do the following:

    RUN pip install pipenv
    RUN cd /my/app/path &amp;&amp; pipenv install
    RUN cd /my/app/path &amp;&amp; pipenv install --system

It is working...

So two question: First: Why is `pipenv shell` giving me this error and Second: Why do I have to do `pipenv install` before `pipenv install --system` to get it working?

I would like to use pipenv to create virtual environments with different python versions and differne dependency versions.


How to get pipenv running in docker?

Is there a way to use pipenv with Jupyter notebook?

Or more specifically, with an atom nteract/hydrogen python 3 kernel?



Is there a way to use pipenv with Jupyter notebook?

I am learning Python virtual environment. In one of my small projects I ran

    pipenv run python myproject.py

and it created a virtualenv for me in `C:\Users\USERNAME\.virtualenvs`

I found it also created or modified some files under my project source code directory. I am just wondering how to cleanly delete this virtualenv and reverse my project back to a no-virtualenv state.

I am using python 3.6.4, and PyCharm.

How to remove a virtualenv created by &quot;pipenv run&quot;

My Ubuntu 16.04.03 is installed with Python 3.5.2. How do I setup pipenv to use Python 3.6 when my system does not have python 3.6?   

    $ pipenv --python 3.6
    Warning: Python 3.6 was not found on your system…
    You can specify specific versions of Python with:
      $ pipenv --python path/to/python



Content Type	Original Author	Original Content on Stackoverflow
Question	Julien Le Coupanec	View Question on Stackoverflow
Solution 1 - Python	wiesson	View Answer on Stackoverflow

Git - Should Pipfile.lock be committed to version control?

Python Problem Overview

Python Solutions

Solution 1 - Python

Angular what's the meaning of these three dots in @NGRX

How to make axios synchronous

Attributions