Characters and strings - Introduction to Programming - Python

Characters and strings

We have been using strings since the very first lesson. 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
`\0`	Null character

In competitive programming, \n and are the only ones you will regularly encounter — mostly in input parsing and output formatting.

Up next

String methods

Python strings come with a rich set of built-in methods. Since strings are immutable, every method returns a new string — the original is never modified.

\t

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

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

Characters and strings

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

`ord()` and `chr()`