Kodeclik Blog
Cloning a Python string
Intro: Do you even need to “clone” a string?
In Python, strings are immutable, which means they cannot be changed after they’re created. That single fact makes “cloning” a string much less important than cloning mutable objects like lists or dictionaries.
If two variables refer to the same string value, nothing dangerous can happen, because neither variable can mutate the underlying string. Still, there are times—especially when learning Python—when you want to create a second variable that contains the same text, or you want to rebuild a string explicitly. This post shows a few practical ways to do that using the string "Kodeclik" as a running example.
Method 1: Assignment Operator (Reference Only)
The simplest method is assignment. When you write clone = original, Python does not create a new string; it simply binds the name clone to the same string object that original already refers to.
With mutable objects, that shared reference can cause surprises, but with strings it’s safe because the string can’t be modified in place. If your goal is simply “I want another variable that has the same text,” assignment is not just acceptable—it’s the normal Pythonic solution.
original = "Kodeclik"
clone = original
print(original) # Kodeclik
print(clone) # KodeclikMethod 2: The str() Constructor
A closely related approach is the str() constructor. If you already have a string, calling str(original) typically returns the same string rather than constructing a brand-new one, because there is no benefit to creating a second identical immutable object.
The real usefulness of str() is when the input might not already be a string, such as an integer, a float, or some custom object. In that case str(x) converts the value into its string representation, and that’s often exactly what you want for printing, logging, or formatting.
original = "Kodeclik"
clone = str(original)
print(clone) # KodeclikHere’s a quick example of str() doing what it’s really meant to do—converting something that isn’t already a string:
visits = 42
s = str(visits)
print(s) # "42"Method 3: Rebuild using the join() method
Another common technique is to rebuild the string using join. If you do "".join(original), Python iterates over the characters of the string and joins them back together into a new string value. In practice, for short strings, it’s mostly educational.
Where join really matters is when you are building a string from many parts, because repeated concatenation can be inefficient while join is designed for exactly that use case.
original = "Kodeclik"
clone = "".join(original)
print(clone) # KodeclikAnd here’s an example where join is the right tool because you’re assembling pieces into a final string:
parts = ["Ko", "de", "cl", "ik"]
result = "".join(parts)
print(result) # KodeclikMethod 4: Full slicing ([:])
You’ll also see people use slicing, like clone = original[:]. This is a popular “copy trick” for lists, and it works syntactically for strings as well. Conceptually, it means “take the entire string from start to end.”
However, because strings are immutable, Python is free to optimize and may return the original object anyway. Even if it does, nothing breaks, because the value is the same and immutable.
Slicing is therefore fine as a teaching example, but it doesn’t usually provide anything that simple assignment doesn’t already give you.
original = "Kodeclik"
clone = original[:]
print(clone) # KodeclikMethod 5: Encode + decode (reconstruct via bytes)
If you want a method that clearly reconstructs the string through a transformation step, you can encode and decode it. This converts the string into bytes and then back into a string again. In real programs, this is useful when you are genuinely crossing a boundary between text and bytes, such as reading from a file or network.
As a cloning method, though, it is overkill, slower, and unnecessary unless you are already working with encoded data.
original = "Kodeclik"
clone = original.encode("utf-8").decode("utf-8")
print(clone) # KodeclikA note on “copying” vs “new object”
A quick note about what people sometimes mean by “clone” is worth making. Sometimes they mean “another variable with the same characters,” and sometimes they mean “a different object in memory with a different identity.” For strings, identity is not something you should rely on, because Python may reuse the same string object in multiple places for performance reasons. If you check object identity with is, you might get different results across runs or implementations, even when the string values are identical. For strings, the meaningful comparison is almost always value equality using ==, not identity using is.
original = "Kodeclik"
clone1 = original
clone2 = str(original)
clone3 = original[:]
clone4 = "".join(original)
print(original == clone4) # True (same characters)
print(original is clone4) # could be True or False depending on optimizationsApplications
In practical code, the most common “copy-like” pattern with strings is simply keeping an original and then producing a derived version. For example, you might keep the raw input " Kodeclik " and also compute a cleaned version using .strip(). The original remains unchanged automatically, because nothing can mutate it.
raw = " Kodeclik "
clean = raw.strip()
print(raw) # " Kodeclik "
print(clean) # "Kodeclik"Another common application is converting non-string values into strings so they can be used in messages, filenames, logs, or UI output. Here str() is doing exactly what it’s designed for:
name = "Kodeclik"
visits = 4200
message = name + " visits: " + str(visits)
print(message) # Kodeclik visits: 4200Finally, when you are building a string from many pieces—especially inside loops or when assembling output—join is often the cleanest and fastest approach:
words = ["Welcome", "to", "Kodeclik"]
sentence = " ".join(words)
print(sentence) # Welcome to KodeclikSummary
The bottom line is that Python makes string “cloning” intentionally boring. Because strings can’t be modified in place, you usually don’t need a special copying technique at all. If you just want another variable holding "Kodeclik", assignment is the cleanest answer. The other methods are mainly useful when you are converting types, building strings from parts, or dealing with bytes in real-world input/output.
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