Python String isnumeric()

Python String isnumeric() function returns True if all the characters in the string are numeric, otherwise False. If the string is empty, then this function returns False.

Python String isnumeric()

Numeric characters include digit characters, and all characters that have the Unicode numeric value property. Formally, numeric characters are those with the property value Numeric_Type=Digit, Numeric_Type=Decimal or Numeric_Type=Numeric.

Let’s look at some examples of Python string isnumeric() function.

s = '2019'

print(s.isnumeric())

Output: True because all the characters in the string are numerical.

s = 'Hello 2019'
print(s.isnumeric())

Output: False because some of the characters in the string are not numerical.

s = ''
print(s.isnumeric())

Output: False because it’s an empty string.

Let’s look into some examples with special Unicode characters that are numerical.

s = '¼'  # 00bc: ¼ (VULGAR FRACTION ONE QUARTER)
print(s)
print(s.isnumeric())

s = '⒈⒗'  #2488: ⒈ (DIGIT ONE FULL STOP), 2497: ⒗ (NUMBER SIXTEEN FULL STOP)
print(s)
print(s.isnumeric())

Output:

¼
True
⒈⒗
True

Print all Unicode Numeric Characters

We can use unicodedata module to print all the unicode characters that are considered as numeric.

import unicodedata

count = 0
for codepoint in range(2 ** 16):
    ch = chr(codepoint)
    if ch.isnumeric():
        print(u'{:04x}: {} ({})'.format(codepoint, ch, unicodedata.name(ch, 'UNNAMED')))
        count = count + 1
print(f'Total Number of Numeric Unicode Characters = {count}')

Output:

0030: 0 (DIGIT ZERO)
0031: 1 (DIGIT ONE)
...
ff16: ６ (FULLWIDTH DIGIT SIX)
ff17: ７ (FULLWIDTH DIGIT SEVEN)
ff18: ８ (FULLWIDTH DIGIT EIGHT)
ff19: ９ (FULLWIDTH DIGIT NINE)
Total Number of Numeric Unicode Characters = 800

I never thought that there will be 800 Unicode characters that are numeric. 🙂

Reference: Official Documentation