Hyppää sisältöön

Ei vielä käännetty

Tätä sivua ei ole vielä käännetty suomeksi, joten se näytetään englanniksi. Auta kääntämään

Textwrap Module Complexity

The textwrap module provides utilities for formatting and wrapping text while preserving formatting like indentation.

Common Operations

Operation Time Space Notes
wrap(text, width) O(n) O(n) Wrap text to width; n = text length
fill(text, width) O(n) O(n) Fill and return string
dedent(text) O(n) O(n) Remove common indent
indent(text, prefix) O(n) O(n) Add prefix to lines
shorten(text, width) O(n) O(n) Shorten to width

Text Wrapping

wrap()

Time Complexity: O(n)

Where n = text length.

from textwrap import wrap

# Wrap text: O(n) where n = characters
text = "This is a long piece of text that needs to be wrapped to fit within a specific width."
lines = wrap(text, width=40)
# ['This is a long piece of text that', 
#  'needs to be wrapped to fit within a',
#  'specific width.']

# Wrap with break_long_words: O(n)
text = "supercalifragilisticexpialidocious"
lines = wrap(text, width=10, break_long_words=True)  # O(n)

# Wrap with break_on_hyphens: O(n)
text = "The mother-in-law was very helpful"
lines = wrap(text, width=20, break_on_hyphens=True)  # O(n)

Space Complexity: O(n)

from textwrap import wrap

# Result list of lines
lines = wrap(long_text, width=40)  # O(n) space for all lines

fill()

Time Complexity: O(n)

from textwrap import fill

# Fill text: O(n) - wraps then joins
text = "This is a long piece of text"
filled = fill(text, width=30)  # O(n)
# "This is a long piece of\ntext"

# With indentation: O(n)
filled = fill(text, width=30, initial_indent=">>> ", subsequent_indent="... ")  # O(n)

Space Complexity: O(n)

from textwrap import fill

# Result string stored
result = fill(long_text, width=40)  # O(n) space

Indentation Handling

dedent()

Time Complexity: O(n)

from textwrap import dedent

# Remove common indent: O(n)
indented = """
    This is indented.
    So is this.
    And this too.
"""
dedented = dedent(indented)  # O(n)
# """
# This is indented.
# So is this.
# And this too.
# """

# Works with mixed indent levels: O(n)
mixed = """
    First line
        Indented more
    Back to first
"""
dedented = dedent(mixed)  # O(n)

Space Complexity: O(n)

from textwrap import dedent

# Result string stored
result = dedent(text)  # O(n) space

indent()

Time Complexity: O(n)

Where n = text length.

from textwrap import indent

# Add indent: O(n) where n = characters
text = "First line\nSecond line\nThird line"
indented = indent(text, "  ")  # O(n)
# "  First line\n  Second line\n  Third line"

# With predicate: O(n) to check each line
indented = indent(text, "# ", predicate=lambda line: not line.startswith("#"))  # O(n)

# Common use: comment code
code = "x = 1\ny = 2"
commented = indent(code, "# ")  # O(n)
# "# x = 1\n# y = 2"

Space Complexity: O(n)

from textwrap import indent

# Result string stored
result = indent(long_text, prefix)  # O(n) space

Text Shortening

shorten()

Time Complexity: O(n)

from textwrap import shorten

# Shorten text: O(n) where n = length
long_text = "This is a very long piece of text that contains lots of words"
shortened = shorten(long_text, width=30)  # O(n)
# "This is a very long piece..."

# With placeholder: O(n)
shortened = shorten(long_text, width=30, placeholder="[...]")  # O(n)
# "This is a very long piece[...]"

# Break on word boundaries: O(n)
text = "Word1 Word2 Word3"
shortened = shorten(text, width=10)  # O(n)
# "Word1 [...]"

Space Complexity: O(n)

from textwrap import shorten

# Result string stored
result = shorten(text, width=40)  # O(n) space

Common Patterns

Format Docstrings

from textwrap import dedent, fill

def my_function():
    """Example function."""
    doc = """
    This function does something.
    It has multiple lines.
    And multiple paragraphs.

    Usage:
        my_function()
    """
    # Clean up indentation
    clean_doc = dedent(doc).strip()
    # Print wrapped
    print(fill(clean_doc, width=70))

Create Indented Code Blocks

from textwrap import indent, dedent

code_snippet = """
def hello():
    print("Hello, world!")
"""

# Indent for documentation
indented = indent(dedent(code_snippet).strip(), "    ")
print("Example:\n" + indented)

Format Help Messages

from textwrap import fill, indent

help_text = "This is a detailed help message that explains all the features and options available to users."

# Wrap and indent
header = "HELP:\n"
wrapped = fill(help_text, width=70)
formatted = header + indent(wrapped, "  ")
print(formatted)

Shorten Long Strings for Display

from textwrap import shorten

def truncate_for_display(text, max_width=50):
    """Show text with ellipsis if too long."""
    return shorten(text, width=max_width, placeholder="...")

description = "This is a very long description that might be too long for a single line display"
short = truncate_for_display(description, 40)
print(short)  # "This is a very long description..."

Performance Characteristics

Best Practices

from textwrap import wrap, fill, dedent

# Good: dedent at source for cleaner code
code = dedent("""
    def hello():
        print("Hello")
""")

# Good: Use fill for single operation
filled = fill(text, width=80)  # O(n)

# Avoid: Multiple operations
lines = wrap(text, width=80)  # O(n)
filled = '\n'.join(lines)      # O(n) again

# Better: Use fill directly
filled = fill(text, width=80)  # O(n) once

Large Text Handling

from textwrap import wrap

# wrap() returns a list, so it still holds all lines in memory
lines = wrap(huge_text, width=80)  # O(n) memory

# For large inputs, wrap per paragraph to limit peak memory
for paragraph in huge_text.split("\n\n"):
    for line in wrap(paragraph, width=80):
        process(line)

TextWrapper Class

Time Complexity: O(1) init, O(n) per format

from textwrap import TextWrapper

# Create wrapper with settings: O(1)
wrapper = TextWrapper(
    width=70,
    initial_indent="* ",
    subsequent_indent="  ",
    break_long_words=False,
)

# Use repeatedly: O(n) per use
wrapped1 = wrapper.wrap("First text")  # O(n)
wrapped2 = wrapper.wrap("Second text")  # O(n)

Version Notes

  • Python 3.3+: indent() function added
  • Python 3.4+: Improvements to wrapping