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The Experiment That Looked Right—but Wasn’t

Best Python package manager for data science wasn’t something I searched for after reading blog posts.
I searched for it after a result I trusted turned out to be wrong.
The notebook ran.
The model trained.
The numbers looked reasonable.
Then I reran the same experiment on a different machine.
Same code.
Same dataset.
Same random seed.
Different outcome.
That’s when I learned a hard lesson:
in data science, your package manager isn’t a convenience tool—it’s part of the experiment.


How I Ended Up Using Every Tool by Accident

I didn’t consciously choose any package manager.

  • pip came with Python
  • conda came with Anaconda
  • mamba showed up in performance tips
  • uv appeared when installs started annoying me
  • poetry entered through a colleague’s project

Tutorials mixed them freely.
Colleagues assumed “it doesn’t matter.”
And for a while, I believed them.
That belief didn’t survive real work.

When environments drift, results drift with them.

Why Data Science Changes Everything

Backend developers mostly deal with Python packages.
Data scientists don’t.

You’re working with:

  • Native math libraries (BLAS, LAPACK, MKL)
  • GPU runtimes (CUDA, cuDNN, ROCm)
  • Platform-specific binaries
  • Complex dependency chains that must align exactly

This is where the question
“what’s the best Python package manager for data science”
stops being theoretical.
You’re not just installing libraries.
You’re assembling a numerical computing system where version mismatches can silently corrupt results.


PIP: The Tool That Works… Until It Doesn’t

My first workflow was simple:

python -m venv .venv
source .venv/bin/activate
pip install numpy pandas scikit-learn matplotlib

For lightweight analysis, it was perfect.

The cracks appeared when I needed:

  • GPU support
  • Numerical consistency across machines
  • Reproducibility in production
pip install torch torchvision torchaudio

Sometimes it installed CUDA.
Sometimes CPU-only.
Sometimes it failed silently and gave me the wrong binary.
pip didn’t break loudly.
It broke subtly.
And subtle failures are deadly in data science.

When pip Still Shines

PIP is still excellent when:

  • Dependencies are pure Python
  • No compiled libraries are involved
  • You’re prototyping quickly
  • Results don’t need cross-machine consistency

Not every notebook needs conda.


Conda: The First Time Things Just Worked

Conda felt heavy—until it saved me from debugging dependency hell.

conda create -n research python=3.10
conda activate research
conda install numpy pandas scikit-learn pytorch cudatoolkit=11.8

Yes, I waited for:

Solving environment...

But when it finished, everything worked.
Same results.
Same performance.
Same behavior on other machines.
That’s when I understood conda’s philosophy.

The Core Difference Most Comparisons Miss

This is the real distinction:
PIP manages Python packages.
CONDA manages entire environments.

PIP assumes:

  • System libraries already exist
  • Wheels are sufficient
  • The OS handles dependencies

CONDA assumes:

  • System dependencies matter
  • Binary compatibility is critical
  • Reproducibility beats minimalism

Neither approach is wrong.
They solve different problems.

Where Conda Starts to Hurt

Conda isn’t free.
I’ve waited minutes for dependency solving.
I’ve fought channel conflicts (conda-forge vs defaults).
I’ve cleaned bloated environments that grew into gigabytes.
Once a conda environment works, you’re afraid to touch it.
That fear is justified.

Conda trades speed and transparency for stability.

Locking Your Conda Environment

For true reproducibility:

# Export exact environment
conda env export > environment.yml

# Or lock specific versions
conda list --export > requirements.txt

This creates a snapshot you can recreate elsewhere.


Mamba: Conda, Without the Waiting

Mamba exists because people loved conda’s guarantees but hated waiting.

mamba create -n research python=3.10
mamba install numpy pandas pytorch cudatoolkit

What mamba changes:

  • Much faster solving (C++ reimplementation)
  • Parallel downloads
  • Better error messages
  • Immediate feedback

What it doesn’t change:

  • Same channels
  • Same environment model
  • Same guarantees

In practice:
mamba is conda for people who got impatient.
If you already trust conda for data science,
mamba is almost always a free upgrade.


UV: Not Just Fast pip Anymore

uv entered my workflow as “blazingly fast pip.”
I didn’t understand why at first—but later I realized exactly why uv is faster than pip when installs stopped interrupting my thinking.


By 2024, it became something more ambitious.

# uv now manages Python versions
uv python install 3.11

# Creates virtual environments natively
uv venv

# Installs packages with aggressive caching
uv pip install numpy pandas scikit-learn

What uv Does Exceptionally Well

  • Lightning-fast installs (10-100x faster than pip)
  • Intelligent caching across projects
  • Built-in virtual environment management
  • Python version management
  • Dependency resolution similar to Poetry

What uv Still Doesn’t Do

  • Manage CUDA toolkits directly
  • Handle all non-Python system libraries
  • Fully replace conda for GPU-heavy ML

uv is evolving rapidly, but it still assumes your system handles the heavy binary dependencies.

When uv Makes Sense

Use uv for:

  • Fast iteration on pure Python tools
  • Quick prototypes
  • CI/CD pipelines where speed matters
  • Developer tooling (linters, formatters, test runners)

I use uv daily for tooling:

uv pip install black ruff pytest ipython

It’s fast, reliable, and disposable.


Poetry: When Your Team Needs Discipline

Poetry didn’t make my original list because I resisted it.
Then I joined a team with messy dependency management.

poetry new data-project
cd data-project
poetry add numpy pandas scikit-learn

What Poetry brings:

  • Dependency locking by default (poetry.lock)
  • Clear separation of dev/prod dependencies
  • Consistent environments across teams
  • Built-in virtual environment management

The pyproject.toml becomes your single source of truth:

[tool.poetry.dependencies]
python = "^3.10"
numpy = "^1.24.0"
pandas = "^2.0.0"
scikit-learn = "^1.3.0"

[tool.poetry.dev-dependencies]
pytest = "^7.4.0"
black = "^23.0.0"

Where Poetry Fits

Poetry shines when:

  • You’re building a package, not just scripts
  • Multiple people need identical environments
  • You need dependency locking without thinking about it
  • Your workflow is primarily Python (not heavy GPU/compiled work)

For teams, Poetry prevents the “works on my machine” problem.
For solo data science? It can feel like overkill.


The Real Answer: Docker

Here’s the uncomfortable truth:
For true reproducibility, none of these tools are enough.

FROM python:3.10-slim

# System dependencies
RUN apt-get update && apt-get install -y \
    build-essential \
    libopenblas-dev

# Python dependencies
COPY requirements.txt .
RUN pip install -r requirements.txt

# Your code
COPY . /app
WORKDIR /app

Docker locks everything:

  • OS version
  • System libraries
  • Python version
  • Package versions

When stakes are high (production, published research, regulatory compliance),
containerization is often the only real answer.

But containers have a cost:

  • Steeper learning curve
  • Slower iteration
  • More infrastructure complexity

For day-to-day work, package managers still win on speed and simplicity.


Putting Them Side by Side (Without Pretending One Wins)

ToolBest ForStrengthWeakness
pipPure Python, quickSimplicity, speedNo native dependencies
condaML/GPU workflowsBinary stabilitySlow solving
mambaFast condaSpeed + conda guaranteesSame complexity
uvDev tools, iterationBlazing fastLimited system libs
PoetryTeam projectsDependency lockingOverkill for notebooks
DockerProduction, researchComplete reproducibilitySlow iteration

This table didn’t decide anything for me.
Experience did.


The Mistake I Made (That Cost Me Weeks)

I tried to force one tool to fit every workflow.

  • pip for GPU-heavy ML → fragile, unpredictable
  • conda for small scripts → unnecessarily heavy
  • uv for CUDA setups → missing critical pieces

The mistake wasn’t the tools.
It was expecting universality.
Once I stopped asking “which is best”
and started asking “what problem am I solving right now”,
everything improved.


The Hybrid Workflow That Finally Stuck

Here’s what I actually do now.

For Serious Data Science and ML:

mamba create -n ml python=3.10
mamba install numpy pandas pytorch cudatoolkit

Why: Binary consistency matters. GPU support must be reliable.

For Fast Iteration and Tooling:

uv pip install black ruff pytest ipython

Why: I reinstall these tools constantly. Speed matters.

For Team Projects:

poetry install

Why: Everyone needs the exact same environment, automatically.

For Production/Research:

# Docker with locked dependencies

Why: Stakes are too high for drift.

The rule is simple:

  • Conda/mamba for the foundation (numerical computing, ML, GPU)
  • uv for the edges (tooling, quick experiments)
  • Poetry for team coordination (shared projects)
  • Docker for stakes that matter (production, publication)

It’s not elegant.
It’s effective.


Why Data Scientists Feel This Pain More Than Others

In data science, failures are rarely loud.
Web servers crash with stack traces.
Models fail silently.

A model can:

  • Train successfully
  • Produce plausible numbers
  • Pass basic validation

But behave differently because NumPy linked against a different BLAS library.
That’s why environment consistency matters more here than almost anywhere else in software.
Backend services crash.
Models lie.


Practical Tips for Each Tool

For pip:

# Always pin versions in production
pip install numpy==1.24.3 pandas==2.0.2

# Use virtual environments
python -m venv .venv
source .venv/bin/activate  # Linux/Mac
# .venv\Scripts\activate   # Windows

# Lock your environment
pip freeze > requirements.txt

For conda/mamba:

# Use conda-forge for most packages
mamba install -c conda-forge numpy pandas

# Export for reproducibility
mamba env export > environment.yml

# Create from export
mamba env create -f environment.yml

# Clean regularly
mamba clean --all

For uv:

# Create project-specific cache
uv pip install --cache-dir .uv-cache numpy

# Use with venv
python -m venv .venv
source .venv/bin/activate
uv pip install -r requirements.txt

For Poetry:

# Lock dependencies
poetry lock

# Install exactly what's locked
poetry install

# Add package to both pyproject.toml and lock
poetry add numpy

# Dev dependencies only
poetry add --group dev pytest

The Questions That Helped Me Choose

Instead of “which is best,” I started asking:

  1. Do I need GPU support? → Conda/mamba
  2. Is this a quick experiment? → pip or uv
  3. Will others run this code? → Poetry or conda
  4. Are these results going in a paper? → Docker
  5. Am I just installing linters? → uv

These questions made decisions obvious.


The Lesson I Carry Forward

The best Python package manager for data science isn’t a single tool.

It’s a decision framework.

  • pip minimizes friction
  • uv minimizes waiting
  • conda minimizes surprises
  • mamba minimizes patience loss
  • Poetry minimizes team conflicts
  • Docker minimizes uncertainty

Once I accepted that and stopped fighting for a “one true tool,”
my environments stopped lying to me.
And for data science, that matters more than speed, elegance, or simplicity.
Because when your model’s predictions influence real decisions,
“it worked on my machine” isn’t good enough.

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