Python Basics: Strings

1. String Basics

A string is a sequence of characters enclosed in single (') or double (") quotes.

Common Operations

text = "Python"

text + " Basics"      # Concatenate strings
text * 3              # Repeat a string
len(text)             # String length

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2. Escape Sequences

Escape sequences represent special characters inside strings.

Escape	Description
\n	New line
\t	Horizontal tab
\\	Backslash (\)
\'	Single quote
\"	Double quote
\r	Carriage return
\f	Form feed
\a	Bell (alert)
\b	Backspace
\0	Null character

Example:

print("Hello\nWorld")

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3. String Slicing

Extract part of a string using indexes.

Syntax

string[start:end]

• start is inclusive.
• end is exclusive.

Example:

text = "Python"

text[0:2]      # "Py"
text[:4]       # "Pyth"
text[2:]       # "thon"
text[-1]       # "n"

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4. String Formatting

% Formatting (Legacy)

"%s" % "Python"
"%d" % 10
"%.2f" % 3.14159

Common format specifiers:

Code	Description
%s	String
%c	Character
%d	Integer
%f	Float
%o	Octal
%x	Hexadecimal
%%	Percent sign

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str.format()

"Hello, {}".format("Python")
"{0} {1}".format("Hello", "World")
"{name}".format(name="Python")

Alignment:

"{:<10}".format("Hi")     # Left
"{:>10}".format("Hi")     # Right
"{:^10}".format("Hi")     # Center
"{:*^10}".format("Hi")    # Fill with *

Floating-point precision:

"{:.2f}".format(3.14159)

Escape braces:

"{{Python}}"

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f-Strings (Recommended)

Available in Python 3.6+.

name = "Python"
version = 3.13

f"{name} {version}"
f"{version:.1f}"
f"{name:>10}"

Supports:

• Variables
• Expressions
• Dictionary access
• Alignment
• Number formatting

Example:

x = 10
y = 20

f"{x} + {y} = {x + y}"

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5. Common String Methods

Search

text.count("a")
text.find("a")
text.index("a")

• count() : Count occurrences.
• find() : Return index, or -1 if not found.
• index() : Return index, or raise ValueError.

Case Conversion

text.upper()
text.lower()

Remove Whitespace

text.strip()
text.lstrip()
text.rstrip()

Replace

text.replace("Python", "Java")

Split

text.split()
text.split(",")

Returns a list of substrings.

Join

",".join(["A", "B", "C"])

Output:

A,B,C

Notes

• Strings are immutable, meaning their contents cannot be changed directly.
• Most string methods return a new string instead of modifying the original.

Note: AI was used to assist in the drafting and formatting of this post.