Python String Copy

Python strings are immutable, which means they cannot be modified once they are created. This characteristic simplifies the process of copying strings because you don’t need to worry about accidentally modifying the original string while working with the copy. To copy a string in Python, you can simply assign the original string to a new variable. This creates a new reference to the same string object, but since strings are immutable, any operation on one reference won’t affect the other

1. Quick Examples of Copying a String

If you are in a hurry, below are some quick examples of copying a string.


# Quick examples of copying a string

# Initialization string
string = "Welcome To SparkByExamples"

# Example 1: Use an empty string 
# To get a copy string
copied_string = '' + string

# Example 2: Copy a string using slicing
copied_string = string[:]

# Example 3: Using str() function
# Copy a string 
copied_string = str(string)

# Example 4: Using string formatting 
# Copy a string 
copied_string = '%s' % string

# Example 5: Using the assignment operator
# Copy the string
copied_string = string

# Example 6: Use Character concatenation through loop
concatenated_string = ""
for char in string:
    concatenated_string = concatenated_string + char

# Example 7: Concatenate using the += operator
concatenated_string = ""
concatenated_string += string

2. Use an Empty String to Get a Copy of the String

You can use an empty string with concatenation effectively creates a copy of the original string. This will create a new string object referenced copied_string that contains the same content as the original string. The content of the original string remains unchanged, and any modifications to copied_string will not affect the original string.


# Initialization string
string = "Welcome To SparkByExamples"
print("Original string:", string)

# Use an empty string 
# to get a copy of the string
copied_string = '' + string
print ("Copy of the string: ",copied_string)

Yields below output. copied string.

This copied_string will be a separate string object with the same content as the string. You can change any modifications to copied string won’t affect the original string.

3. Get Copy of the String Using a Slicing

You can also use string slicing to create a copy of an existing string. For example, the slicing string[:] effectively creates a new string with the same content as the original string. The copied_string variable references this new string, which is an independent copy of the original string. Any changes to copied_string will not affect the string variable.


# Initialization string
string = "Welcome To SparkByExamples"
print("Original string:", string)

# Copy a string using slicing
copied_string = string[:]
print ("Copy of the string: ",copied_string)

4. Get Copy of a String Using the str() Function

Alternatively, you can use the str() function to create a new string that is a copy of the original string. Using str(string) creates a new string object with the same content as the string variable. The copied_string variable references this new string object. It’s an independent copy of the original string, and any changes to copied_string will not affect the string variable.


# Initialization string
string = "Welcome To SparkByExamples"
print("Original string:", string)

# Using str() function
# Copy a string 
copied_string = str(string)
print ("Copy of the string: ",copied_string)

5. Create Copy of a String Using String Formatting

You can also use string formatting to create a copy of a string. For example, using this ‘%s‘ % string approach, you are effectively creating a new string with the same content as the original string. The copied_string variable references this new string object.


# Initialization string
string = "Welcome To SparkByExamples"
print("Original string:", string)

# Using string formatting 
# Copy a string 
copied_string = '%s' % string
print ("Copy of the string: ",copied_string)

6. Using Assignment Operator

Use the assignment operator (=) to create a copy of a string in Python. However, it’s important to note that strings are immutable, so when you assign a string to a new variable, you’re effectively creating a reference to the same string object. Any modifications to the new variable will not affect the original string.


# Initialization string
string = "Welcome To SparkByExamples"
print("Original string:", string)

# Using the assignment operator
# Copy the string
copied_string = string
print("Copy of the string:", copied_string)

7. Use Character Concatenation Through Loop

You can copy a string by concatenating characters of the original string to an empty string using a for loop. In the loop, each character from the string is iterated over and concatenated to the concatenated_string variable. This process effectively creates a new string that is a copy of the original string.

This method works, but as mentioned earlier, it’s not the most efficient way to concatenate strings due to the immutable nature of strings. For better performance, consider using methods like str.join() or using a list to collect characters and then join them into a string.


# Initialization string
string = "Welcome To SparkByExamples"
print("Original string:", string)

# Character concatenation through loop
concatenated_string = ""
for char in string:
    concatenated_string = concatenated_string + char
print("Copy of the string:", concatenated_string)

8. Using Concatenation With an Entire String

You can concatenate an entire string to another string using the += operator or by using the + operator. For example, the += operator appends the content of the string variable to the concatenated_string variable.


# Initialization string
string = "Welcome To SparkByExamples"
print("Original string:", string)

# Concatenate using the += operator
concatenated_string = ""
concatenated_string += string
print("Concatenated string:", concatenated_string)

9. Conclusion

In this article, I have explained how to copy a Python string using + operator, slicing, str(), string formatting, for loop, and = assignment operator with examples.

Happy Learning !!