String comparison is the process of checking whether two strings are equal or determining their alphabetical (lexicographical) order.

Python compares strings using the standard comparison operators such as ==, !=, <, >, <=, and >=.

When comparing strings, Python compares the characters one by one using their Unicode values. If the first characters are the same, Python continues comparing the next characters until a difference is found.

String comparison is commonly used for validating user input, sorting text, checking passwords, and making decisions in programs.

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Syntax #

string1 operator string2

Components #

Component	Description
string1	First string to compare.
operator	Comparison operator (==, !=, <, >, <=, >=).
string2	Second string to compare.

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Example 1: Equality Comparison (==) #

main.py

first = "Python"
second = "Python"

print(first == second)

Output #

True

Explanation #

• Both strings contain the same characters.
• Python compares each character.
• Since they are identical, the result is True.

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Example 2: Inequality Comparison (!=) #

main.py

first = "Python"
second = "Java"

print(first != second)

Output #

True

Explanation #

• The strings are different.
• Therefore, they are not equal.
• The != operator returns True.

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Example 3: Alphabetical Comparison #

main.py

print("Apple" < "Banana")

Output #

True

Explanation #

• Python compares the first characters.
• 'A' comes before 'B' in Unicode.
• Therefore, "Apple" is considered smaller than "Banana".

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Example 4: Comparing Strings with Different Cases #

main.py

print("Python" == "python")

Output #

False

Explanation #

• Python comparisons are case-sensitive.
• Uppercase P and lowercase p have different Unicode values.
• Therefore, the strings are not equal.

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Example 5: Greater Than Comparison #

main.py

print("cat" > "car")

Output #

True

Explanation #

• The first two characters (c and a) are the same.
• Python compares the third characters.
• 't' comes after 'r', so the result is True.

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Example 6: User Input Comparison #

main.py

password = input("Enter password: ")

print(password == "python123")

Sample Input #

python123

Output #

True

Explanation #

• The user enters a password.
• Python compares it with the expected string.
• The comparison returns True only if both strings match exactly.

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Example 7: Comparing Prefixes #

main.py

print("abc" < "abcd")

Output #

True

Explanation #

• The first three characters are identical.
• "abc" ends before "abcd".
• Therefore, the shorter string is considered smaller.

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Example 8: Comparing Numeric Strings #

main.py

print("100" < "20")

Output #

True

Explanation #

• Python compares strings character by character.
• '1' comes before '2'.
• The comparison is based on characters, not numeric values.

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Example 9: Using lower() for Case-Insensitive Comparison #

main.py

first = "Python"
second = "python"

print(first.lower() == second.lower())

Output #

True

Explanation #

• lower() converts both strings to lowercase.
• The converted strings become identical.
• This technique is commonly used for case-insensitive comparisons.

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Example 10: Checking the Result Type #

main.py

result = "Python" == "Python"

print(result)
print(type(result))

Output #

True
<class 'bool'>

Explanation #

• String comparison returns either True or False.
• The result is of type bool.

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Common Mistakes #

1. Assuming Comparisons Ignore Case #

Incorrect

print("Python" == "python")

Incorrect Expectation #

True

Actual Output #

False

Reason

String comparisons are case-sensitive.

Correct

print("Python".lower() == "python".lower())

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2. Confusing Numeric Strings with Numbers #

Incorrect

print("100" > "20")

Incorrect Expectation #

True

Actual Output #

False

Reason

Python compares the characters '1' and '2', not the numeric values.

Correct

print(int("100") > int("20"))

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3. Using Assignment Instead of Comparison #

Incorrect

text = "Python"

if text = "Python":
    print("Match")

Output #

SyntaxError: invalid syntax

Reason

Use == for comparison.
The = operator is used only for assignment.

Correct

if text == "Python":
    print("Match")

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4. Assuming Strings of Different Lengths Cannot Be Compared #

Incorrect

print("abc" < "abcd")

Incorrect Expectation #

Error

Actual Output #

True

Reason

Python can compare strings of different lengths lexicographically.

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Best Practices #

• Use == to check whether two strings are identical.
• Remember that string comparisons are case-sensitive.
• Use lower() or upper() when performing case-insensitive comparisons.
• Convert numeric strings to integers before numeric comparisons.
• Use descriptive variable names when comparing strings.

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Key Points to Remember #

• Strings can be compared using comparison operators.
• Python compares strings character by character.
• Comparisons are based on Unicode values.
• String comparisons are case-sensitive.
• Comparison results are of type bool.
• Numeric strings are compared as text, not numbers.
• Use lower() or upper() for case-insensitive comparisons.