How do I split the definition of a long string over multiple lines?

python

string-management

best-practices

sql-injection

byAnton Shumikhin·Aug 9, 2024

To manage long strings in Python, use either triple quotes """ for multi-line strings or parentheses () to concatenate shorter strings without using plus signs +.

Example with Triple Quotes:

long_string = """Line one
Line two
Line three"""

Example with Parentheses:

long_string = ("Line one "
               "Line two "
               "Line three")

Both methods maintain code cleanliness, improving readability while reducing manual concatenation — ideal for lengthy scripts or text.

Essential Guidelines

To effectively split and manage strings over multiple lines, consider these important best practices:

Concatenation without Plus Signs

Implicit concatenation using parentheses offers clarity and convenience:

clear_concat = ("Concatenating strings "
                "across multiple lines "
                "improves code readability.")

💡 Be aware!:

Forgetting spaces can lead to unintentionally merged words: ("hello""world") results in "helloworld".
Including a comma unknowingly creates a tuple: ("hello", "world").

Using Variables in Strings

Utilize f-strings for an efficient, secure way to interpolate variables or expressions:

user = "Alice"
message = f"Hello, {user}!"
#"Hello, Alice!" is much better than "Hello, Variable!"

✔️ F-strings offer efficiency and readability, making your Python code not just look fabulous but feel fabulous too.

Security Considerations

When building strings, particularly in SQL queries, focus on security:

# DON'T: This might open doors to SQL injection (and nobody likes unwanted guests!)
query_bad = "SELECT * FROM users WHERE name = '" + user_name + "'"

# DO: Parameterized queries or ORM tools advocates string safety (Better safe than sorry!)
# (Example using a hypothetical ORM interface)
query_good = ORMInterface.select().from_table("users").where(name=user_name)

Remember to always sanitize input and use the right methods to prevent potential exploitation.

Mastering Whitespace in Multi-line Strings

When it comes to multi-line strings, whitespace management can be a game-changer:

Trimming Unwanted Spaces

Ensure your multi-line strings start and end cleanly by removing unwanted spaces:

trimmed_string = """\
This string starts and ends without extra spaces.\
"""
# No extra spaces were harmed in the making of this string

⚠️ Don't let unwanted spaces sneak into your strings due to indentation.

Formulating Readable SQL Queries

Ensure large SQL statements remain readable yet compact:

eloquent_query = (
    "SELECT id, username "
    "FROM users "
    "WHERE status = 1 "
    "ORDER BY join_date DESC"
)
# A well-indented query is a happy query

A combination of triple quotes and parentheses ensures a formatted SQL statement that's easy on the eyes!

Balancing Readability with Efficiency

While readability and efficiency often work together, larger strings require special care:

Use .join() for combining strings efficiently when dealing with a list.
Consider a string builder approach for highly dynamic string concatenation scenarios.

⚡ It's all about finding the right balance!

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