How to Print a Variable's Name in Python

# Table of Contents

# Print a variable's name in Python

To print a variable's name:

Use a formatted string literal to get the variable's name and value.
Split the string on the equal sign and get the variable's name.
Use the print() function to print the variable's name.

main.py

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site = 'bobbyhadz.com'

result = f'{site=}'
print(result)  # 👉️ site='bobbyhadz.com'

# ✅ print variable name using f-string
variable_name = f'{site=}'.split('=')[0]
print(variable_name)  # 👉️ 'site'

print variable name in python

The code for this article is available on GitHub

We used a formatted string literal to get a variable's name as a string.

As shown in the code sample, the same approach can be used to print a variable's name and value.

Formatted string literals (f-strings) let us include expressions inside of a string by prefixing the string with f.

main.py

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var1 = 'bobby'
var2 = 'hadz'

result = f'{var1}{var2}'
print(result)  # 👉️ bobbyhadz

Make sure to wrap expressions in curly braces - {expression}.

Formatted string literals also enable us to use the format specification mini-language in expression blocks.

main.py

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site = 'bobbyhadz.com'

result = f'{site=}'
print(result)  # 👉️ site='bobbyhadz.com'

The equal sign after the variable is used for debugging and returns the variable's name and its value.

The expression expands to:

The text before the equal sign.
An equal sign.
The result of calling the repr() function with the evaluated expression.

To get only the variable name, we have to split the string on the equal sign and return the first list item.

main.py

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site = 'bobbyhadz.com'

variable_name = f'{site=}'.split('=')[0]
print(variable_name)  # 👉️ 'site'

The str.split() method splits the string into a list of substrings using a delimiter.

main.py

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site = 'bobbyhadz.com'

result = f'{site=}'
print(result)  # 👉️ site='bobbyhadz.com'

print(result.split('='))  # 👉️ ['site', "'bobbyhadz.com'"]

The method takes the following 2 parameters:

Name	Description
`separator`	Split the string into substrings on each occurrence of the separator
`maxsplit`	At most `maxsplit` splits are done (optional)

You can use the str.join() method if you need to join the variable's name and value with a different separator.

main.py

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website = 'bobbyhadz'

result = ':'.join(f'{website=}'.split('='))
print(result)  # 👉️ website:'bobbyhadz'

The str.join() method takes an iterable as an argument and returns a string which is the concatenation of the strings in the iterable.

The string the method is called on is used as the separator between the elements.

Alternatively, you can use the globals() function.

# Print a variable's name using globals()

This is a three-step process:

Use the globals() function to get a dictionary that implements the current module namespace.
Iterate over the dictionary to get the matching variable's name.
Use the print() function to print the variable's name.

main.py

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def get_var_name(variable):
    globals_dict = globals()

    return [
        var_name for var_name in globals_dict
        if globals_dict[var_name] is variable
    ]


site = 'bobbyhadz.com'

print(get_var_name(site))  # 👉️ ['site']

print(get_var_name(site)[0])  # 👉️ 'site'

print variable name using globals

The code for this article is available on GitHub

You can tweak the function if you also need to get the value.

main.py

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def get_variable_name_value(variable):
    globals_dict = globals()

    return [
        f'{var_name}={globals_dict[var_name]}'
        for var_name in globals_dict
        if globals_dict[var_name] is variable
    ]


website = 'bobbyhadz.com'

 # 👇️ ['website=bobbyhadz.com']
print(get_variable_name_value(website))

# 👇️ website=bobbyhadz.com
print(get_variable_name_value(website)[0])

The globals function returns a dictionary that implements the current module namespace.

main.py

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site = 'bobbyhadz.com'

globals_dict = globals()

# {'site': 'bobbyhadz.com', '__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x7f235932dde0>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, '__file__': '/home/borislav/Desktop/bobbyhadz_python/main.py', '__cached__': None,  'globals_dict': {...}}
print(globals_dict)

We used a list comprehension to iterate over the dictionary.

main.py

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site = 'bobbyhadz.com'

globals_dict = globals()

result = [key for key in globals_dict]

# ['__name__', '__doc__', '__package__', '__loader__', '__spec__', '__annotations__', '__builtins__', '__file__', '__cached__', 'site', 'globals_dict']
print(result)

List comprehensions are used to perform some operation for every element or select a subset of elements that meet a condition.

On each iteration, we check if the identity of the provided variable matches the identity of the current dictionary value.

main.py

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def get_var_name(variable):
    globals_dict = globals()

    return [var_name for var_name in globals_dict if globals_dict[var_name] is variable]


site = 'bobbyhadz.com'

print(get_var_name(site))  # 👉️ ['site']

print(get_var_name(site)[0])  # 👉️ 'site'

The matching variable names (keys in the dictionary) get returned as a list.

# Having multiple variables with the same value

If you have multiple variables with the same value, pointing to the same location in memory, the list would contain multiple variable names.

main.py

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site = 'bobbyhadz.com'
domain = 'bobbyhadz.com'


def get_var_name(variable):
    globals_dict = globals()

    return [
        var_name for var_name in globals_dict
        if globals_dict[var_name] is variable
    ]


print(get_var_name(site))  # 👉️ ['site', 'domain']

having multiple variables with same value

The code for this article is available on GitHub

There are 2 variables with the same value and they point to the same location in memory, so the list returns 2 variable names.

# Objects are stored at a different location in memory

If you pass non-primitive objects to the function, you'll get a list containing only one item because the objects are stored in different locations in memory.

main.py

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class Employee():
    pass

alice = Employee()
bobby = Employee()

def get_var_name(variable):
    globals_dict = globals()

    return [
      var_name for var_name in globals_dict
      if globals_dict[var_name] is variable
    ]


print(get_var_name(alice))  # 👉️ ['alice']

objects are stored at different location in memory

The code for this article is available on GitHub

The two class instances are stored in different locations in memory, so the get_var_name() function returns a list containing a single variable name.

# Print a variable's name using locals()

You can also use the locals() dictionary to print a variable's names.

main.py

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site = 'bobbyhadz.com'

print(locals().items())

variable_name = [
    key for key, value in locals().items()
    if value == 'bobbyhadz.com'
]

print(variable_name)  # 👉️ ['site']
print(variable_name[0])  # 👉️ site

print variable name using locals

The locals() function returns a dictionary that contains the current scope's local variables.

main.py

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site = 'bobbyhadz.com'

# {'site': 'bobbyhadz.com', '__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x7fe25e71f9d0>, '__spec__': None, '__annotations__': {},
# '__builtins__': <module 'builtins' (built-in)>, '__file__': '/home/borislav/Desktop/bobbyhadz_python/main.py', '__cached__': None}
print(locals())

We used a list comprehension to print the variable that has a value of bobbyhadz.com.

# The globals() dictionary vs the locals() dictionary

This approach is similar to using the globals() dictionary, however, the locals() function returns a dictionary that contains the current scope's local variables, whereas the globals dictionary contains the current module's namespace.

Here is an example that demonstrates the difference between the globals() and the locals() dictionaries.

main.py

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global_site = 'bobbyhadz.com'


def print_variable_name():
    local_site = 'bobbyhadz.com'

    local_name = [
        key for key, value in locals().items()
        if value == 'bobbyhadz.com'
    ]

    print(f'local_name {local_name}')

    # -----------------------------------------------

    globals_dict = globals()

    global_name = [
        var_name for var_name in globals_dict
        if globals_dict[var_name] == 'bobbyhadz.com'
    ]

    print(f'global_name {global_name}')


# local_name ['local_site']
# global_name ['global_site']
print_variable_name()

The code for this article is available on GitHub

The function uses the locals() and globals() dictionaries to print the name of the variable that has a value of bobbyhadz.com.

There is a variable with the specified value in the global and local scopes.

The locals() dictionary prints the name of the local variable, whereas the globals() dictionary prints the name of the global variable.

# Print a variable's name by storing it in a dictionary

An alternative approach is to store the variable's name as a value in a dictionary.

main.py

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my_dict = {
    'bobbyhadz': 'site',
    'python': 'language',
}

print(my_dict['bobbyhadz'])  # 👉️ site
print(my_dict['python'])  # 👉️ language

The code sample stores the values of the variables as keys in the dictionary and the names of the variables as values.

Here is an easier way to visualize this.

main.py

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site = 'bobbyhadz'
language = 'python'

# ----------------------------------

my_dict = {
    'bobbyhadz': 'site',
    'python': 'language',
}

print(my_dict['bobbyhadz'])  # 👉️ site
print(my_dict['python'])  # 👉️ language

The approach is similar to a reverse mapping.

By swapping the dictionary's keys and values, we can access variable names by values.

You can define a reusable function to make it more intuitive.

main.py

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def get_name(dictionary, value):
    return dictionary[value]


my_dict = {
    'bobbyhadz': 'site',
    'python': 'language',
}

print(get_name(my_dict, 'bobbyhadz'))  # 👉️ site

print(get_name(my_dict, 'python'))  # 👉️ language

The code for this article is available on GitHub

The function takes a dictionary and a value as parameters and returns the corresponding name.

I've also written an article on how to assign print output to a variable.

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

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How to Print a Variable's Name in Python

# Table of Contents

# Print a variable's name in Python

# Print a variable's name using globals()

# Having multiple variables with the same value

# Objects are stored at a different location in memory

# Print a variable's name using locals()

# The globals() dictionary vs the locals() dictionary

# Print a variable's name by storing it in a dictionary

# Additional Resources

Borislav Hadzhiev