Python String isdecimal() Methods

The isdecimal() method returns True if all characters in a string are decimal characters. If not, it returns False.

Decimal characters are those that can be used to form numbers in base 10. All the Unicode General Category 'Nd' are considered as decimal characters.

Syntax:

str.isdecimal()

Parametrs:

None.

Return Value:

Returns True if all characters in the string are decimals; otherwise returns False even if one character is not decimal.

The following examples demonstrate isdecimal() method.

numstr = '12345'
print(numstr.isdecimal()) # returns True

numstr = '10.50'
print(numstr.isdecimal()) # returns False

alnumstr = '123A'
print(alnumstr.isdecimal()) # returns False

mystr = 'Python'
print(mystr.isdecimal()) # returns False

True
False
False
False

The isdecimal() method will return False if a string contains whitespaces, symbols or alphabets.

amount = '$100'
print(amount.isdecimal())

code = '#007'
print(mystr.isdecimal())

False
False

All the characters under Unicode General Category 'Nd' are decimals e.g. isdecimal() returns True for the Arabic decimal two is ٢ decimal.

arabicdecimal = '٢'  # 2 in Arabic
print(arabicdecimal.isdecimal())

True

Superscript and subscripts (usually written using unicode) are considered digit characters and not decimal. Hence, if the string contains these characters along with decimal characters, isdecimal() returns False.

mystr = '\u00B23455'     # returns subscript 2 with the number 3455
print(mystr.isdecimal())

mystr = '\u2156' # Unicode chars of ⅖
print(mystr.isdecimal())

mystr = '\u0032' # Unicode chars of 2
print(mystr.isdecimal())

False
False
True

The following table lists difference among the isdecimal(), isdigit(), and isnumeric() methods based on the given inputs: