Problem Formulation and Solution Overview

In this article, you’ll learn how to increment a dictionary value in Python.

To make it more fun, we have the following running scenario:

Trinity Bank keeps track of its latest mortgage rates in a Dictionary format. Recently there has been a steady increase in rates. How would Trinity Bank increment/increase the Dictionary value of a selected rate?

mtg_rates = {'30-Year-Fixed': 5.625, '20-Year-Fixed': 5.250, '10-Year-Variable': 5.125, '7-Year-Variable': 5.011, '5-Year-Variable': 4.625}

Question: How would we write code to increment a Dictionary value in Python?

We can accomplish this task by one of the following options:

• Method 1: Use Dictionary Key Name
• Method 2: Use Dictionary.get()
• Method 3: Use Dictionary.update()
• Method 4: Use Unpacking using the * Operator
• Method 5: Use Dictionary Comprehension

---

Method 1: Use Dictionary Key Name

This method passes an existing Dictionary Key Name to access and increment the appropriate Value.

mtg_rates['30-Year-Fixed'] += 1

print(mtg_rates['30-Year-Fixed'])

In this example, the 30-Year-Fixed mortgage rate is referenced by name (mtg_rates['30-Year-Fixed']) and its value is incremented by one (1).

Then, this updated value is saved back to mtg_rates['30-Year-Fixed'] and output to the terminal.

6.625

---

Method 2: Use Dictionary.get()

This method uses the Dictionary.get() method and passes a Dictionary Key as an argument to retrieve and increment the corresponding Value.

mtg_rates['20-Year-Fixed'] = mtg_rates.get('20-Year-Fixed') + 2

print(mtg_rates['20-Year-Fixed'])

In this example, the 20 Year Fixed mortgage rate is referenced and accessed using (mtg_rates.get('20-Year-Fixed')). This value is then incremented by two (2).

Then, this updated value is saved back to mtg_rates['20-Year-Fixed'] and output to the terminal.

7.25

---

Method 3: Use Dictionary.update()

This method uses Dictionary.update() to reference the appropriate Key and increment the Value.

new_rate = mtg_rates['10-Year-Variable'] + 3

mtg_rates.update({'10-Year-Variable': new_rate})

print(mtg_rates['10-Year-Variable'])

In this example, the current value of a 10 Year Variable mortgage rate is retrieved, incremented by three (3) and saved to new_rate.

Next, the appropriate Key for the key:value pair is accessed, and the Value is updated to reflect the contents of new_rate and output to the terminal.

8.125

---

Method 4: Use Unpacking

This method uses Unpacking to increment the Value of a key:value pair.

mtg_rates = {**mtg_rates, '7-Year-Variable': 9.011}

print(mtg_rates)

Above, accesses the 7 Year Variable mortgage rate, increments the rate to the amount indicated (9.011), and outputs it to the terminal.

9.011

---

Method 5: Use Dictionary Comprehension

This method increments all Mortgage Rates in one fell swoop using Dictionary Comprehension.

new_rates = dict(((key, round(value*1.10, 3)) for key, value in mtg_rates.items()))

print(new_rates)

Above, accesses each mortgage rate in the mtg_rates Dictionary and increments the rate by 1.10. Then, round() is called to round the results down to three (3) decimal places. The result saves to new_rates and output to the terminal.

{'30-Year-Fixed': 6.188, '20-Year-Fixed': 5.775, '10-Year-Variable': 5.638, '7-Year-Variable': 5.512, '5-Year-Variable': 5.088}

---

Summary

These methods of incrementing a Dictionary Value should give you enough information to select the best one for your coding requirements.

Good Luck & Happy Coding!

---

Regex Humor

In this article, I’ll show you:

How to check the version of the Python module (package, library) future? And how to check if future is installed anyways?

These are the eight best ways to check the installed version of the Python module future:

• Method 1: pip show future
• Method 2: pip list
• Method 3: pip list | findstr future
• Method 4: library.__version__
• Method 5: importlib.metadata.version
• Method 6: conda list
• Method 7: pip freeze
• Method 8: pip freeze | grep future

Before we go into these ways to check your future version, let’s first quickly understand how versioning works in Python—you’ll be thankful to have spent a few seconds on this topic, believe me!

A Note on Python Version Numbering

Python versioning adds a unique identifier to different package versions using semantic versioning. Semantic versioning consists of three numerical units of versioning information in the format major.minor.patch.

In this tutorial, we’ll use the shorthand general version abbreviation like so:

x.y.z

Practical examples would use numerical values for x, y, and z:

• 1.2.3
• 4.1.4
• 1.0.0

This is shorthand for

major.minor.patch

• Major releases (0.1.0 to 1.0.0) are used for the first stable release or “breaking changes”, i.e., major updates that break backward compatibility.
• Minor releases (0.1.0 to 0.2.0) are used for larger bug fixes and new features that are backward compatible.
• Patch releases (0.1.0 to 0.1.1) are used for smaller bug fixes that are backward compatible.

Let’s dive into the meat of this article:

Question: How to check the (major, minor, patch) version of future in your current Python environment?

Method 1: pip show

To check which version of the Python library future is installed, run pip show future or pip3 show future in your CMD/Powershell (Windows), or terminal (macOS/Linux/Ubuntu).

This will work if your pip installation is version 1.3 or higher—which is likely to hold in your case because pip 1.3 was released a decade ago in 2013!!

Here’s an example in my Windows Powershell: I’ve highlighted the line that shows that my package version is a.b.c:

PS C:\Users\xcent> pip show future

Name: future

Version: a.b.c

Summary: ...

Home-page: ...

Author: ...

Author-email: ...

License: ...

Location: ...

Requires: ...

Required-by: ...

In some instances, this will not work—depending on your environment. In this case, try those commands before giving up:

python -m pip show future

python3 -m pip show future

py -m pip show future

pip3 show future

Next, we’ll dive into more ways to check your future version.

But before we move on, I’m excited to present you my new Python book Python One-Liners (Amazon Link).

If you like one-liners, you’ll LOVE the book. It’ll teach you everything there is to know about a single line of Python code. But it’s also an introduction to computer science, data science, machine learning, and algorithms. The universe in a single line of Python!

The book was released in 2020 with the world-class programming book publisher NoStarch Press (San Francisco).

Link: https://nostarch.com/pythononeliners

Method 2: pip list

To check the versions of all installed packages, use pip list and locate the version of future in the output list of package versions sorted alphabetically.

This will work if your pip installation is version 1.3 or higher.

Here’s a simplified example for Windows Powershell, I’ve highlighted the line that shows the package version is 1.2.3:

PS C:\Users\xcent> pip list

Package Version

--------------- ---------

aaa 1.2.3

...

future 1.2.3

...

zzz 1.2.3

In some instances, this will not work—depending on your environment. Then try those commands before giving up:

python -m pip list

python3 -m pip list

py -m pip list

pip3 list 

Method 3: pip list + findstr on Windows

To check the versions of a single package on Windows, you can chain pip list with findstr future using the CMD or Powershell command: pip3 list | findstr future to locate the version of future in the output list of package versions automatically.

Here’s an example for future:

pip3 list | findstr future 1.2.3

Method 4: Module __version__ Attribute

To check which version is installed of a given library, you can use the library.__version__ attribute after importing the library (package, module) with import library.

Here’s the code:

import my_library

print(my_library.__version__)

# x.y.z for your version output

Here’s an excerpt from the PEP 8 docs mentioning the __version__ attribute.

“PEP 8 describes the use of a module attribute called __version__ for recording “Subversion, CVS, or RCS” version strings using keyword expansion. In the PEP author’s own email archives, the earliest example of the use of an __version__ module attribute by independent module developers dates back to 1995.”

You can also use the following one-liner snippet to run this from your terminal (macOS, Linux, Ubuntu) or CMD/Powershell (Windows):

python3 -c "import my_library; print(my_library.__version__)"

However, this method doesn’t work for all libraries, so while simple, I don’t recommend it as a general approach for that reason.

Method 5: importlib.metadata.version

The importlib.metadata library provides a general way to check the package version in your Python script via importlib.metadata.version('future') for library future. This returns a string representation of the specific version such as 1.2.3 depending on the concrete version in your environment.

Here’s the code:

import importlib.metadata

print(importlib.metadata.version('future'))

# 1.2.3

Method 6: conda list

If you have created your Python environment with Anaconda, you can use conda list to list all packages installed in your (virtual) environment. Optionally, you can add a regular expression using the syntax conda list regex to list only packages matching a certain pattern.

How to list all packages in the current environment?

conda list

How to list all packages installed into the environment 'xyz'?

conda list -n xyz

Regex: How to list all packages starting with 'future'?

conda list '^future'

Method 7: pip freeze

The pip freeze command without any option lists all installed Python packages in your environment in alphabetically order (ignoring UPPERCASE or lowercase). You can spot your specific package future if it is installed in the environment.

pip freeze

Output example (depending on your concrete environment/installation):

PS C:\Users\xcent> pip freeze

aaa==1.2.3

...

future==1.2.3

...

zzz==1.2.3

---

You can modify or exclude specific packages using the options provided in this screenshot:

Method 8: pip freeze + grep on Linux/Ubuntu/macOS

To check the versions of a single package on Linux/Ubuntu/macOS, you can chain pip freeze with grep future using the CMD or Powershell command: pip freeze | grep future to programmatically locate the version of your particular package future in the output list of package versions.

Here’s an example for future:

pip freeze | grep future

future==1.2.3

Related Questions

Check future Installed Python

How to check if future is installed in your Python script?

To check if future is installed in your Python script, you can run import future in your Python shell and surround it by a try/except to catch a potential ModuleNotFoundError.

try: import future print("Module future installed")

except ModuleNotFoundError: print("Module future not installed")

Check future Version Python

How to check the package version of future in Python?

To check which version of future is installed, use pip show future or pip3 show future in your CMD/Powershell (Windows), or terminal (macOS/Linux/Ubuntu) to obtain the output major.minor.patch.

pip show future # or pip3 show future

# 1.2.3

Check future Version Linux

How to check my future version in Linux?

To check which version of future is installed, use pip show future or pip3 show future in your Linux terminal.

pip show future # or pip3 show future

# 1.2.3

Check future Version Ubuntu

How to check my future version in Ubuntu?

To check which version of future is installed, use pip show future or pip3 show future in your Ubuntu terminal.

pip show future # or pip3 show future

# 1.2.3

Check future Version Windows

How to check my future version on Windows?

To check which version of future is installed, use pip show future or pip3 show future in your Windows CMD, command line, or PowerShell.

pip show future # or pip3 show future

# 1.2.3

Check future Version Mac

How to check my future version on macOS?

To check which version of future is installed, use pip show future or pip3 show future in your macOS terminal.

pip show future # or pip3 show future

# 1.2.3

Check future Version Jupyter Notebook

How to check my future version in my Jupyter Notebook?

To check which version of future is installed, add the line !pip show future to your notebook cell where you want to check. Notice the exclamation mark prefix ! that allows you to run commands in your Python script cell.

!pip show future

Output: The following is an example on how this looks for future in a Jupyter Notebook cell:

Package Version

--------------- ---------

aaa 1.2.3

...

future 1.2.3

...

zzz 1.2.3

Check future Version Conda/Anaconda

How to check the future version in my conda installation?

Use conda list 'future' to list version information about the specific package installed in your (virtual) environment.

conda list 'future'

Check future Version with PIP

How to check the future version with pip?

You can use multiple commands to check the future version with PIP such as pip show future, pip list, pip freeze, and pip list.

pip show future

pip list

pip freeze

pip list

The former will output the specific version of future. The remaining will output the version information of all installed packages and you have to locate future first.

Check Package Version in VSCode or PyCharm

How to check the future version in VSCode or PyCharm?

Integrated Development Environments (IDEs) such as VSCode or PyCharm provide a built-in terminal where you can run pip show future to check the current version of future in the specific environment you’re running the command in.

pip show future

pip3 show future pip list

pip3 list pip freeze

pip3 freeze

You can type any of those commands in your IDE terminal like so:

Summary

In this article, you’ve learned those best ways to check a Python package version:

• Method 1: pip show future
• Method 2: pip list
• Method 3: pip list | findstr future
• Method 4: library.__version__
• Method 5: importlib.metadata.version
• Method 6: conda list
• Method 7: pip freeze
• Method 8: pip freeze | grep future

Thanks for giving us your valued attention — we’re grateful to have you here!

---

Programmer Humor

There are only 10 kinds of people in this world: those who know binary and those who don’t.

~~~

There are 10 types of people in the world. Those who understand trinary, those who don’t, and those who mistake it for binary.

Related Tutorials

• How to Check Your Python Version
• How to Check Your Module Version
• How to Create a Python Module
• Start Learning Python
• How to Become a Freelance Developer
• PIP Commands – A Simple Guide

In this article, I’ll show you:

How to check the version of the Python module (package, library) abc? And how to check if abc is installed anyways?

These are the eight best ways to check the installed version of the Python module abc:

• Method 1: pip show abc
• Method 2: pip list
• Method 3: pip list | findstr abc
• Method 4: library.__version__
• Method 5: importlib.metadata.version
• Method 6: conda list
• Method 7: pip freeze
• Method 8: pip freeze | grep abc

Before we go into these ways to check your abc version, let’s first quickly understand how versioning works in Python—you’ll be thankful to have spent a few seconds on this topic, believe me!

A Note on Python Version Numbering

Python versioning adds a unique identifier to different package versions using semantic versioning. Semantic versioning consists of three numerical units of versioning information in the format major.minor.patch.

In this tutorial, we’ll use the shorthand general version abbreviation like so:

x.y.z

Practical examples would use numerical values for x, y, and z:

• 1.2.3
• 4.1.4
• 1.0.0

This is shorthand for

major.minor.patch

• Major releases (0.1.0 to 1.0.0) are used for the first stable release or “breaking changes”, i.e., major updates that break backward compatibility.
• Minor releases (0.1.0 to 0.2.0) are used for larger bug fixes and new features that are backward compatible.
• Patch releases (0.1.0 to 0.1.1) are used for smaller bug fixes that are backward compatible.

Let’s dive into the meat of this article:

Question: How to check the (major, minor, patch) version of abc in your current Python environment?

Method 1: pip show

To check which version of the Python library abc is installed, run pip show abc or pip3 show abc in your CMD/Powershell (Windows), or terminal (macOS/Linux/Ubuntu).

This will work if your pip installation is version 1.3 or higher—which is likely to hold in your case because pip 1.3 was released a decade ago in 2013!!

Here’s an example in my Windows Powershell: I’ve highlighted the line that shows that my package version is a.b.c:

PS C:\Users\xcent> pip show abc

Name: abc

Version: a.b.c

Summary: ...

Home-page: ...

Author: ...

Author-email: ...

License: ...

Location: ...

Requires: ...

Required-by: ...

In some instances, this will not work—depending on your environment. In this case, try those commands before giving up:

python -m pip show abc

python3 -m pip show abc

py -m pip show abc

pip3 show abc

Next, we’ll dive into more ways to check your abc version.

But before we move on, I’m excited to present you my new Python book Python One-Liners (Amazon Link).

If you like one-liners, you’ll LOVE the book. It’ll teach you everything there is to know about a single line of Python code. But it’s also an introduction to computer science, data science, machine learning, and algorithms. The universe in a single line of Python!

The book was released in 2020 with the world-class programming book publisher NoStarch Press (San Francisco).

Link: https://nostarch.com/pythononeliners

Method 2: pip list

To check the versions of all installed packages, use pip list and locate the version of abc in the output list of package versions sorted alphabetically.

This will work if your pip installation is version 1.3 or higher.

Here’s a simplified example for Windows Powershell, I’ve highlighted the line that shows the package version is 1.2.3:

PS C:\Users\xcent> pip list

Package Version

--------------- ---------

aaa 1.2.3

...

abc 1.2.3

...

zzz 1.2.3

In some instances, this will not work—depending on your environment. Then try those commands before giving up:

python -m pip list

python3 -m pip list

py -m pip list

pip3 list 

Method 3: pip list + findstr on Windows

To check the versions of a single package on Windows, you can chain pip list with findstr abc using the CMD or Powershell command: pip3 list | findstr abc to locate the version of abc in the output list of package versions automatically.

Here’s an example for abc:

pip3 list | findstr abc 1.2.3

Method 4: Module __version__ Attribute

To check which version is installed of a given library, you can use the library.__version__ attribute after importing the library (package, module) with import library.

Here’s the code:

import my_library

print(my_library.__version__)

# x.y.z for your version output

Here’s an excerpt from the PEP 8 docs mentioning the __version__ attribute.

“PEP 8 describes the use of a module attribute called __version__ for recording “Subversion, CVS, or RCS” version strings using keyword expansion. In the PEP author’s own email archives, the earliest example of the use of an __version__ module attribute by independent module developers dates back to 1995.”

You can also use the following one-liner snippet to run this from your terminal (macOS, Linux, Ubuntu) or CMD/Powershell (Windows):

python3 -c "import my_library; print(my_library.__version__)"

However, this method doesn’t work for all libraries, so while simple, I don’t recommend it as a general approach for that reason.

Method 5: importlib.metadata.version

The importlib.metadata library provides a general way to check the package version in your Python script via importlib.metadata.version('abc') for library abc. This returns a string representation of the specific version such as 1.2.3 depending on the concrete version in your environment.

Here’s the code:

import importlib.metadata

print(importlib.metadata.version('abc'))

# 1.2.3

Method 6: conda list

If you have created your Python environment with Anaconda, you can use conda list to list all packages installed in your (virtual) environment. Optionally, you can add a regular expression using the syntax conda list regex to list only packages matching a certain pattern.

How to list all packages in the current environment?

conda list

How to list all packages installed into the environment 'xyz'?

conda list -n xyz

Regex: How to list all packages starting with 'abc'?

conda list '^abc'

Method 7: pip freeze

The pip freeze command without any option lists all installed Python packages in your environment in alphabetically order (ignoring UPPERCASE or lowercase). You can spot your specific package abc if it is installed in the environment.

pip freeze

Output example (depending on your concrete environment/installation):

PS C:\Users\xcent> pip freeze

aaa==1.2.3

...

abc==1.2.3

...

zzz==1.2.3

---

You can modify or exclude specific packages using the options provided in this screenshot:

Method 8: pip freeze + grep on Linux/Ubuntu/macOS

To check the versions of a single package on Linux/Ubuntu/macOS, you can chain pip freeze with grep abc using the CMD or Powershell command: pip freeze | grep abc to programmatically locate the version of your particular package abc in the output list of package versions.

Here’s an example for abc:

pip freeze | grep abc

abc==1.2.3

Related Questions

Check abc Installed Python

How to check if abc is installed in your Python script?

To check if abc is installed in your Python script, you can run import abc in your Python shell and surround it by a try/except to catch a potential ModuleNotFoundError.

try: import abc print("Module abc installed")

except ModuleNotFoundError: print("Module abc not installed")

Check abc Version Python

How to check the package version of abc in Python?

To check which version of abc is installed, use pip show abc or pip3 show abc in your CMD/Powershell (Windows), or terminal (macOS/Linux/Ubuntu) to obtain the output major.minor.patch.

pip show abc # or pip3 show abc

# 1.2.3

Check abc Version Linux

How to check my abc version in Linux?

To check which version of abc is installed, use pip show abc or pip3 show abc in your Linux terminal.

pip show abc # or pip3 show abc

# 1.2.3

Check abc Version Ubuntu

How to check my abc version in Ubuntu?

To check which version of abc is installed, use pip show abc or pip3 show abc in your Ubuntu terminal.

pip show abc # or pip3 show abc

# 1.2.3

Check abc Version Windows

How to check my abc version on Windows?

To check which version of abc is installed, use pip show abc or pip3 show abc in your Windows CMD, command line, or PowerShell.

pip show abc # or pip3 show abc

# 1.2.3

Check abc Version Mac

How to check my abc version on macOS?

To check which version of abc is installed, use pip show abc or pip3 show abc in your macOS terminal.

pip show abc # or pip3 show abc

# 1.2.3

Check abc Version Jupyter Notebook

How to check my abc version in my Jupyter Notebook?

To check which version of abc is installed, add the line !pip show abc to your notebook cell where you want to check. Notice the exclamation mark prefix ! that allows you to run commands in your Python script cell.

!pip show abc

Output: The following is an example on how this looks for abc in a Jupyter Notebook cell:

Package Version

--------------- ---------

aaa 1.2.3

...

abc 1.2.3

...

zzz 1.2.3

Check abc Version Conda/Anaconda

How to check the abc version in my conda installation?

Use conda list 'abc' to list version information about the specific package installed in your (virtual) environment.

conda list 'abc'

Check abc Version with PIP

How to check the abc version with pip?

You can use multiple commands to check the abc version with PIP such as pip show abc, pip list, pip freeze, and pip list.

pip show abc

pip list

pip freeze

pip list

The former will output the specific version of abc. The remaining will output the version information of all installed packages and you have to locate abc first.

Check Package Version in VSCode or PyCharm

How to check the abc version in VSCode or PyCharm?

Integrated Development Environments (IDEs) such as VSCode or PyCharm provide a built-in terminal where you can run pip show abc to check the current version of abc in the specific environment you’re running the command in.

pip show abc

pip3 show abc pip list

pip3 list pip freeze

pip3 freeze

You can type any of those commands in your IDE terminal like so:

Summary

In this article, you’ve learned those best ways to check a Python package version:

• Method 1: pip show abc
• Method 2: pip list
• Method 3: pip list | findstr abc
• Method 4: library.__version__
• Method 5: importlib.metadata.version
• Method 6: conda list
• Method 7: pip freeze
• Method 8: pip freeze | grep abc

Thanks for giving us your valued attention — we’re grateful to have you here!

---

Programmer Humor

There are only 10 kinds of people in this world: those who know binary and those who don’t.

~~~

There are 10 types of people in the world. Those who understand trinary, those who don’t, and those who mistake it for binary.

Related Tutorials

• How to Check Your Python Version
• How to Check Your Module Version
• How to Create a Python Module
• Start Learning Python
• How to Become a Freelance Developer
• PIP Commands – A Simple Guide