Modify a String In-Place in Python

Unfortunately, you cannot modify a string in place because strings are immutable. Simply create a new string from the several parts you want to gather it from. Though, if you still need an object with the ability to modify in-place unicode data, you should for

• The io.StringIO object
• The Array module

Let's see what we discussed above ?

Return a string with the entire contents of the buffer

Example

In this example, we will return a string with the entire contents of the buffer. We have a text stream StringIO ?

import io

myStr = "Hello, How are you?"
print("String = ",myStr)

# StringIO is a text stream using an in-memory text buffer
strIO = io.StringIO(myStr)

# The getvalue() returns a string containing the entire contents of the buffer
print(strIO.getvalue())

Output

String = Hello, How are you?
Hello, How are you?

Now, let us change the stream position, write new content and display

Change the stream position and write new String

Example

We will see another example and change the stream position using the seek() method. A new string will be written at the same position using the write() method ?

import io
myStr = "Hello, How are you?"

# StringIO is a text stream using an in-memory text buffer
strIO = io.StringIO(myStr)

# The getvalue() returns a string containing the entire contents of the buffer
print("String = ",strIO.getvalue())

# Change the stream position using seek()
strIO.seek(7)

# Write at the same position
strIO.write("How's life?")

# Returning the final string
print("Final String = ",strIO.getvalue())

Output

String = Hello, How are you?
Final String = Hello, How's life??

Create an array and convert it to Unicode string

Example

In this example, create an array using array() and then convert it to the Unicode string using the tounicode() method ?

import array

# Create a String
myStr = "Hello, How are you?"

# Array
arr = array.array('u',myStr)
print(arr)

# Modifying the array
arr[0] = 'm'

# Displaying the array
print(arr)

# convert an array to a unicode string using tounicode
print(arr.tounicode())

Output

array('u', 'Hello, How are you?')
array('u', 'mello, How are you?')
mello, How are you?