Lernen Erstellen und Überprüfen von Strings

Strings are how Python stores text - names, messages, file paths, even emoji. In Python 3, strings are Unicode by default, so they can represent characters from virtually any language.

What Is a String?

A string is an immutable sequence of characters. "Immutable" means you don't change a string in place. Instead, operations create a new string.


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# Displaying a course title with an icon
course_title = "Data Types in Python"
status_emoji = "🚀"

print(course_title, status_emoji)  # Output: Python for Beginners 🚀

Creating Strings

Python lets you write string literals with single or double quotes. Choose whichever makes the code clearer.


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# Showing how to handle quotes correctly in user messages
greeting = "Hello!"
message = 'User said: "Hi, nice to meet you!"'
note = "It's fine to mix single and double quotes in text."

print(greeting)
print(message)
print(note)

If you need multiple lines, use triple-quoted strings. Python keeps the line breaks.


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# Creating a multi-line email template
email_template = """Dear User,
Your subscription has been successfully renewed.
Thank you for staying with us!"""

print(email_template)

To include special characters (like a newline) in a single line, use escape sequences.


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# Formatting a welcome message for the user
welcome_message = "Welcome to Codefinity!\nLet's start your learning journey."
print(welcome_message)

When backslashes should be taken literally (e.g., Windows paths or simple regex patterns), a raw string helps.


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# Storing a file path on a Windows system
file_path = r"C:\Users\alex\Documents\report.pdf"  # backslashes are kept as-is
print(file_path)

Inspecting Strings (without indexing yet)

You'll often need quick checks: "what is this?" and "how long is it?"


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s = "hello"
print(type(s))     # <class 'str'>
print(len(s))      # 5

An empty string is considered falsey, while any non-empty string is truthy. That's handy in conditions.


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# Checking if the user entered their username during login
username = ""

if username:
    print(f"Welcome back, {username}!")
else:
    print("Please enter your username")  # runs because an empty string is falsey

Note

"" (empty) is not the same as " " (a space). len("") == 0, len(" ") == 1;
\n counts as one character (a newline), so len("A\nB") == 3;
Prefer raw strings for paths to avoid accidental escapes like "\t" (tab).

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Abschnitt 3. Kapitel 1

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