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We discussed some string functions in ‘Built-in String Functions’. There are some more essential functions which are discussed here.

String Functions in Python3
String Function in Python 3

1. isalpha()

Returns true if string contains only alphabetic letters, false otherwise.
Syntax:- str.isalpha()

Note: – Whitespace characters and special characters are not considered in this group.

Example: –
>>>str="Python"
>>>print(str.isalpha())
True
>>>str="Python!"
>>>print(str.isalpha())
False
>>>#Returns False as string contains exclamation mark (special character)
>>>str="Power of Python" #Here string contains whitespace characters.
>>>print(str.isalpha())
False

2. islower()

Returns true if all characters in the string are lowercase, false otherwise.
Syntax: – str.islower()

Example: –
>>>str="Python"
>>>print(str.islower())
False
>>>str="python!"
>>>print(str.islower())
True 
>>>#Here special characters are allowed.
>>>str="Power of Python" #Here string contains whitespace characters.
>>>print(str.islower())
True #Whitespaces are also allowed

3. isupper()

Returns true if all characters in the string are uppercase, false otherwise.
Syntax:- str.upper()

Example: –
>>>str="WELCOMe"
>>>print(str.isupper())
False
>>>str="PROGRAMMING THROUGH PYTHON!"
>>>print(str.isupper())
True 
>>>#Here special characters are allowed.
#Whitespaces are also allowed

4. istitle()

Returns true if string is properly titled-case. Returns False if the string is not title cased or empty.
Syntax: – str.istitle()

Example: –
>>>str="Learn Python"
>>>print(str.istitle())
True
>>>str=Bahut scope Hain Engineering Mein
>>>print(str.istitle())
False
>>>str=" "
>>>print(str.istitle())
False

5. isnumeric()

Returns true if all characters of the string are numeric characters. Otherwise, it returns False.
Numeric characters include all integers, fractions, subscript, superscript, Roman numerals etc.

Note: –It is advised to go through Python documentation once.
Syntax: – str.isnumeric()

Example:-
>>>str="1 2 3 4 5"
>>>print(str.isnumeric())
False 
>>>#It contains whitespace also
>>>str="134653"
>>>print(str.isnumeric())
True

Code to find all numeric characters in unicode

import sys
t=[]
for i in range(sys.maxunicode + 1):
    s = chr(i)
    if s.isnumeric():
        t.append(s)
print(*t,end=" ")

6. isspace()

Returns true if string contains only whitespace characters, false otherwise.
Syntax:- str.isspace()

Example:-
>>str=" "
>>>print(str.isspace())
True
>>>str=" Welcome                 "
>>>print(str.isspace())
False
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Kapil Bansal

A student of B.Tech CSE working on competitive programming, a cybersecurity devotee working towards strengthing the concepts. I am also working on Python modules, Data Structures and Algorithms etc.

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