How Can I Dynamically Create Variables in Python Based on String Values?

Variable Substitution for Strings

When you need to create a variable based on the value of a string, the typical approach is to use assignment. However, this technique becomes problematic when you want to reassign the original string value.

Suppose you have a string variable foo assigned to the string "bar". To define a new variable based on the value of foo, you might attempt the following:

foo = "bar"
foo = "something else"

This code will raise an error because Python will reassign the value of foo to "something else", instead of creating a new variable named bar.

Dynamic Variable Creation with exec()

To achieve the desired behavior of creating a new variable based on a string value, you can employ the exec() function. exec() dynamically executes Python code, allowing you to construct variables programmatically.

Here's how to use exec() to create a variable based on a string:

foo = "bar"
exec(foo + " = 'something else'")
print(bar)  # Outputs "something else"

In this example, exec() executes the string bar = 'something else', effectively creating a new variable named bar with the value "something else".

This technique is particularly useful when you need to generate variables dynamically based on external input or in situations where the variable names are unknown at compile time.

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