mutable-print 1.0.3

Edit printed terminal text using ANSI escape codes.

mutable-print

Edit printed terminal text using ANSI escape codes.

Why Mutable Print?

Traditional print() writes output that cannot be changed once printed. mutable-print fixes that you can modify, replace, append, clear, or transform text after it’s been printed.

Perfect for:

• Dynamic CLI output: progress bars, live status updates, etc.
• Retroactive edits: fix or adjust lines even after more output follows.
• Readable terminals: no messy reprints or repeated lines.
• Rich text operations: prepend, append, regex replacement, upper/lower transforms.

All achieved using ANSI escape sequences to move the cursor and redraw content.

Installation

pip install mutable-print

Usage (API Overview)

mutable_print(*args: Any, sep: str = " ", end: str = "\n", file: Optional[TextIO] = None, flush: bool = False) -> mutable_print

Creates a mutable print object, prints the initial content immediately, and returns a handle to modify it later.

from mutable_print import mutable_print

line = mutable_print("Loading...", flush=True)
line("Done!")  # Update the same printed line

Parameters

Name	Type	Default	Description
*args	Any	—	Values to print
sep	str	" "	Separator between values
end	str	"\n"	String appended at the end
file	TextIO	sys.stdout	Output stream
flush	bool	False	Whether to flush immediately

Returns

A mutable_print instance that can be updated or transformed.

---

__call__(*args: Any, sep: str = " ", end: str = "\n") -> None

Update the content and reprint from this line onward.

line("Processing...", sep=" ", end="\n")

Parameters

Name	Type	Default	Description
*args	Any	—	New values to print
sep	str	" "	Separator
end	str	"\n"	End string

---

replace(old: str, new: str, count: int = -1) -> mutable_print

Replace all (or a limited number of) occurrences of a substring in the current content.

line.replace("fail", "success", 1)

Parameters

Name	Type	Default	Description
old	str	—	Substring to replace
new	str	—	Replacement text
count	int	-1	Max occurrences (-1 for all)

---

append(*text: str) -> mutable_print

Append text to the end of the content.

line.append("...done")

Parameters

Name	Type	Description
*text	str	Text strings to append

---

prepend(*text: str) -> mutable_print

Prepend text to the beginning of the content.

line.prepend("[INFO]")

Parameters

Name	Type	Description
*text	str	Text strings to prepend

---

clear() -> mutable_print

Clear the current content (sets it to an empty string).

line.clear()

---

set(*text: str) -> mutable_print

Replace the entire content with new text.

line.set("New content")

Parameters

Name	Type	Description
*text	str	Text strings to set as new content

---

upper() -> mutable_print

Convert the current content to uppercase.

line.upper()

---

lower() -> mutable_print

Convert the current content to lowercase.

line.lower()

---

regex_replace(pattern: str | re.Pattern[str], replacement: str, flags: int = 0) -> mutable_print

Perform a regular expression substitution on the content.

line.regex_replace(r"\d+", "42")

Parameters

Name	Type	Default	Description
pattern	str | re.Pattern	—	Regex pattern
replacement	str	—	Replacement string (supports backrefs)
flags	int	0	Regex flags (e.g. re.IGNORECASE)

---

get() -> str

Retrieve the current content.

text = line.get()

---

__str__() -> str

String representation of the current content. Called automatically by str(line).

---

__repr__() -> str

Developer-friendly representation of the object:

mutable_print('Your content here')

Examples

1. Basic Update
2. Clean and Efficient Loading
3. Replace Text
4. Append / Prepend
5. Clearing and Retrieving Content
6. Colored Text

How it works?

Internally, mutable-print:

• Keeps a global list of all printed lines.
• Calculates the cursor position relative to past prints.
• Moves the cursor up using \033[A and clears lines with \033[2K.
• Reprints from the updated index to maintain correct order.

This enables retroactive edits even after printing additional lines.

Credits

Developed with ❤️ by PcoiDev Uses only standard Python modules (sys, re, typing).

License

This project is licensed under the MIT License.