Complete List of Python String Validation Methods

Python provides several built-in string methods to check if a string meets certain criteria. These methods return True or False and are useful for input validation, data cleaning, and text processing.

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1. Case Checking Methods

Method	Description	Example
isupper()	Checks if all characters are uppercase	"HELLO".isupper() → True
islower()	Checks if all characters are lowercase	"hello".islower() → True
istitle()	Checks if the string is in title case (first letter of each word capitalized)	"Python Code".istitle() → True

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2. Character Type Validation

Method	Description	Example
isalpha()	Checks if all characters are alphabetic (a-z, A-Z)	"Python".isalpha() → True
isdigit()	Checks if all characters are digits (0-9)	"123".isdigit() → True
isnumeric()	Checks if all characters are numeric (includes Unicode numbers)	"Ⅷ".isnumeric() → True
isdecimal()	Checks if all characters are decimal (0-9 and Unicode decimal numbers)	"12.5".isdecimal() → False
isalnum()	Checks if all characters are alphanumeric (letters or digits)	"Python123".isalnum() → True

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3. Whitespace & Format Checking

Method	Description	Example
isspace()	Checks if all characters are whitespace ( , \t, \n, etc.)	" \t\n".isspace() → True
isprintable()	Checks if all characters are printable (non-printable chars like \x00 return False)	"Hello".isprintable() → True

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4. ASCII & Unicode Validation

Method	Description	Example
isascii()	Checks if all characters are ASCII (Unicode code point ≤ 127)	"Python".isascii() → True
isidentifier()	Checks if the string is a valid Python identifier (variable name)	"var_name".isidentifier() → True

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5. Specialized Checks

Method	Description	Example
startswith(prefix)	Checks if the string starts with prefix	"Hello".startswith("He") → True
endswith(suffix)	Checks if the string ends with suffix	"world".endswith("ld") → True

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Summary Table of All Methods

Method	Returns True If
isupper()	All uppercase letters
islower()	All lowercase letters
istitle()	Title case (each word capitalized)
isalpha()	Only alphabetic letters (a-z, A-Z)
isdigit()	Only digits (0-9)
isnumeric()	Only numeric characters (includes Unicode)
isdecimal()	Only decimal digits (0-9 and Unicode decimals)
isalnum()	Only alphanumeric (letters or digits)
isspace()	Only whitespace ( , \t, \n)
isprintable()	All characters are printable
isascii()	All characters are ASCII (Unicode ≤ 127)
isidentifier()	Valid Python identifier (variable name)
startswith(prefix)	String starts with prefix
endswith(suffix)	String ends with suffix

1. s.isupper()

Checks if all characters in the string are uppercase letters.

Examples:

python

print("HELLO".isupper())  # True
print("Hello".isupper())  # False (contains lowercase 'e')
print("123ABC".isupper()) # True (numbers allowed, but letters must be uppercase)

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2. s.islower()

Checks if all characters in the string are lowercase letters.

Examples:

python

print("hello".islower())  # True
print("Hello".islower())  # False (contains uppercase 'H')
print("123abc".islower()) # True (numbers allowed, but letters must be lowercase)

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3. s.istitle()

Checks if the string is in title case (first letter of each word capitalized, rest lowercase).

Examples:

python

print("Python Programming".istitle())  # True
print("python programming".istitle())  # False
print("Python programming".istitle())  # False (second word not capitalized)

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4. s.isalnum()

Checks if the string contains only alphanumeric characters (letters a-z, A-Z, and digits 0-9).

Examples:

python

print("Python123".isalnum())  # True
print("Python_123".isalnum()) # False (contains underscore)
print("123".isalnum())        # True
print("Python".isalnum())     # True

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5. s.isalpha()

Checks if the string contains only alphabetic characters (letters a-z, A-Z).

Examples:

python

print("Python".isalpha())  # True
print("Python123".isalpha())  # False (contains digits)
print("123".isalpha())     # False

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6. s.isspace()

Checks if the string contains only whitespace characters ( , \t, \n, etc.).

Examples:

python

print("   ".isspace())  # True
print("\t\n".isspace())  # True
print("Hello".isspace())  # False

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7. s.isascii()

Checks if all characters in the string are ASCII (Unicode code point <= 127).

Examples:

python

print("Python".isascii())  # True
print("Pythön".isascii())  # False (contains 'ö', a non-ASCII character)
print("123#!".isascii())   # True

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Summary Table

Method	Checks For	Example (True)	Example (False)
isupper()	All uppercase letters	"HELLO"	"Hello"
islower()	All lowercase letters	"hello"	"Hello"
istitle()	Title case (each word capitalized)	"Python Code"	"python code"
isalnum()	Only letters & digits	"Python123"	"Python_123"
isalpha()	Only letters	"Python"	"Python123"
isspace()	Only whitespace	" \t\n"	"Hello"
isascii()	Only ASCII characters	"Python"	"Pythön"

These methods are useful for input validation, data cleaning, and text processing. Let me know if you need more examples! 😊

Unicode & ASCII-Based String Validation Methods in Python

These methods help determine if a string contains specific types of characters (digits, numbers, decimals, or alphanumeric). They are particularly useful when working with Unicode characters beyond standard ASCII (0-127).

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1. isdigit()

Checks if all characters are digits (0-9 and some Unicode digits like superscripts).

Examples:

python

print("123".isdigit())        # True (ASCII digits)
print("²³⁴".isdigit())        # True (Unicode superscripts)
print("12.5".isdigit())       # False (decimal point not allowed)
print("१२३".isdigit())        # True (Devanagari digits)

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2. isnumeric()

Checks if all characters are numeric (digits, fractions, Roman numerals, etc.).

Examples:

python

print("123".isnumeric())      # True (ASCII digits)
print("Ⅷ".isnumeric())        # True (Roman numeral 8)
print("¾".isnumeric())        # True (Vulgar fraction)
print("12.5".isnumeric())     # False (decimal point not numeric)

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3. isdecimal()

Checks if all characters are decimal digits (0-9 and some Unicode decimals).

Examples:

python

print("123".isdecimal())      # True (ASCII digits)
print("१२३".isdecimal())      # True (Devanagari digits)
print("²³⁴".isdecimal())      # False (superscripts are digits but not decimals)
print("12.5".isdecimal())     # False (decimal point not allowed)

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4. isalnum()

Checks if all characters are alphanumeric (letters a-z, A-Z, or digits 0-9, including Unicode).

Examples:

python

print("Python123".isalnum())  # True (ASCII letters & digits)
print("Pythön123".isalnum())  # True (Unicode 'ö' is alphabetic)
print("१२३abc".isalnum())     # True (Devanagari digits + ASCII letters)
print("Python_123".isalnum()) # False (underscore not allowed)

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Key Differences

Method	ASCII (0-9)	Unicode Digits (², ¾, Ⅷ)	Letters (a-z, A-Z)	Others (_, ., etc.)
isdigit()	✅ Yes	✅ Yes (superscripts, etc.)	❌ No	❌ No
isnumeric()	✅ Yes	✅ Yes (fractions, Roman numerals)	❌ No	❌ No
isdecimal()	✅ Yes	✅ Only decimal digits (Devanagari, etc.)	❌ No	❌ No
isalnum()	✅ Yes	✅ Yes (if digits)	✅ Yes	❌ No

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When to Use Which?

• isdigit() → Check if a string is a valid integer (including superscripts).
• isnumeric() → Check if a string represents any numeric value (including fractions).
• isdecimal() → Strictly check for decimal digits (useful for number parsing).
• isalnum() → Validate usernames, passwords (letters + digits only).

हिंदी अंक (1 से 10) के यूनिकोड कोड पॉइंट्स

हिंदी (देवनागरी) अंकों के यूनिकोड प्रतिनिधित्व की पूरी सूची यहां दी गई है:

अंक	हिंदी अंक	यूनिकोड कोड	यूनिकोड नाम
0	०	U+0966	DEVANAGARI DIGIT ZERO
1	१	U+0967	DEVANAGARI DIGIT ONE
2	२	U+0968	DEVANAGARI DIGIT TWO
3	३	U+0969	DEVANAGARI DIGIT THREE
4	४	U+096A	DEVANAGARI DIGIT FOUR
5	५	U+096B	DEVANAGARI DIGIT FIVE
6	६	U+096C	DEVANAGARI DIGIT SIX
7	७	U+096D	DEVANAGARI DIGIT SEVEN
8	८	U+096E	DEVANAGARI DIGIT EIGHT
9	९	U+096F	DEVANAGARI DIGIT NINE
10	१०	U+0967 U+0966	ONE + ZERO

पायथन में उपयोग के उदाहरण

python

# हिंदी अंकों को प्रिंट करना
hindi_numbers = ["०", "१", "२", "३", "४", "५", "६", "७", "८", "९"]
for num in hindi_numbers:
    print(num, end=' ')
# आउटपुट: ० १ २ ३ ४ ५ ६ ७ ८ ९

# यूनिकोड कोड का उपयोग करके
print("\n१०")  # U+0967 (१) + U+0966 (०)

# isdigit() और isnumeric() के साथ जांच
num = "१२३"
print(num.isdigit())   # True
print(num.isnumeric()) # True
print(num.isdecimal()) # True

महत्वपूर्ण तथ्य

1. ये सभी अंक isdigit(), isnumeric() और isdecimal() के लिए True रिटर्न करते हैं
2. यूनिकोड रेंज: U+0966 से U+096F तक
3. 10 को दर्शाने के लिए ‘१’ और ‘०’ को संयोजित करें (U+0967 + U+0966)

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Telugu Numbers (0 to 10) with Unicode Codes

Here’s the complete list of Telugu numerals with their Unicode representations:

Number	Telugu Numeral	Unicode Code	Unicode Name
0	౦	U+0C66	TELUGU DIGIT ZERO
1	౧	U+0C67	TELUGU DIGIT ONE
2	౨	U+0C68	TELUGU DIGIT TWO
3	౩	U+0C69	TELUGU DIGIT THREE
4	౪	U+0C6A	TELUGU DIGIT FOUR
5	౫	U+0C6B	TELUGU DIGIT FIVE
6	౬	U+0C6C	TELUGU DIGIT SIX
7	౭	U+0C6D	TELUGU DIGIT SEVEN
8	౮	U+0C6E	TELUGU DIGIT EIGHT
9	౯	U+0C6F	TELUGU DIGIT NINE
10	౧౦	U+0C67 U+0C66	ONE + ZERO

Python Examples with Telugu Numbers

python

# Printing Telugu numbers 0-10
telugu_nums = ["౦", "౧", "౨", "౩", "౪", "౫", "౬", "౭", "౮", "౯"]
for num in telugu_nums:
    print(num, end=' ')
# Output: ౦ ౧ ౨ ౩ ౪ ౫ ౬ ౭ ౮ ౯ 

# Printing 10 in Telugu
print("\n౧౦")  # U+0C67 (౧) + U+0C66 (౦)

# Validation checks
num = "౧౨౩"
print(num.isdigit())    # True
print(num.isnumeric())  # True
print(num.isdecimal())  # True

Key Features

1. All Telugu digits return True for isdigit(), isnumeric(), and isdecimal()
2. Unicode range: U+0C66 to U+0C6F
3. To represent 10, combine ‘౧’ (ONE) and ‘౦’ (ZERO)

Additional Information

• These digits are part of the Telugu script block in Unicode (U+0C00 to U+0C7F)
• They are used in the Telugu language, primarily spoken in the Indian states of Andhra Pradesh and Telangana
• The numerals follow the Hindu-Arabic numeral system positional notation