Characters and strings - Programming Language Python for Competitive Programming

Characters and strings

String basics

Characters & String Basics

We have been using strings since the very first lesson — every print("Hello World") contains one. Now let's look at strings properly and understand how they work under the hood.

What is a String?

A string is a sequence of characters. In Python, strings have the type str:

You can use either double quotes or single quotes — both are valid:

For multi-line strings, use triple quotes:

Special Characters and Escape Sequences

Some characters cannot be typed directly inside a string — like a newline or a tab. These are written using escape sequences: a backslash \ followed by a letter.

Output of the first two:

The most important escape sequences:

Sequence	Meaning
`\n`	Newline
`\t`	Horizontal tab
`\\`	Literal backslash `\`
`\"`	Double quote (inside `"..."`)
`\'`	Single quote (inside `'...'`)
`\r`	Carriage return

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String methods

print("Hello\nWorld")    # newline — moves to next line
print("A\tB\tC")         # tab — inserts horizontal whitespace
print("She said \"hi\"") # escaped double quote inside double-quoted string
print('It\'s fine')      # escaped single quote inside single-quoted string
print("C:\\Users\\file") # literal backslash — must be doubled

# Without raw string — every \\ must be escaped
path = "C:\\Users\\username\\Documents"

# With raw string — backslashes are literal
path = r"C:\Users\username\Documents"

print(path)   # C:\Users\username\Documents

print("apple" == "apple")    # True
print("apple" != "orange")   # True
print("apple" < "banana")    # True  — 'a' < 'b'
print("abc" < "abd")         # True  — first two chars equal, 'c' < 'd'
print("ABC" < "abc")         # True  — uppercase letters have smaller codes

Characters and strings

Characters & String Basics

What is a String?

Special Characters and Escape Sequences

Raw Strings

Characters

`ord()` and `chr()`

Strings are Immutable

Strings are Sequences

Length

Indexing

Slicing

Iteration

Membership

String Concatenation and Repetition

Comparing Strings

String and Number Conversion

Characters and strings

Characters & String Basics

What is a String?

Special Characters and Escape Sequences

Raw Strings

Characters

ord() and chr()

Strings are Immutable

Strings are Sequences

Length

Indexing

Slicing

Iteration

Membership

String Concatenation and Repetition

Comparing Strings

String and Number Conversion

`ord()` and `chr()`