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Practice

Case Conversion Methods upper() and lower()

How can you convert the string "apple" to "APPLE", or "APPLE" to "apple" in one step?

Python provides methods upper() and lower() to change the case of characters in a string.


Using Case Conversion Methods​

The upper() method converts all characters in a string to uppercase, while the lower() method converts them to lowercase.

Case Conversion Example
text = "Hello World!"

upper_text = text.upper()

# HELLO WORLD!
print("upper_text:", upper_text)

lower_text = text.lower()

# hello world!
print("lower_text:", lower_text)

When is Case Conversion Needed?​

In programming, case conversion is mainly used during normalization, where user input is transformed into a consistent, standard format.

What is Normalization? : Normalization is the process of converting data into a consistent format. Common tasks include transforming all text to lowercase or removing spaces to facilitate comparison.


Data Normalization Example
user_input = "PyThOn"

standardized_input = user_input.lower()

if standardized_input == "python":
    print("Matched!")
else:
    print("Not Matched.")

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