STRING FUNCTIONS AND METHODS IN PYTHON Python-ல் String data-ஐ process செய்ய, analyze செய்ய, search செய்ய, mo……
STRING FUNCTIONS
String Function String மீது வேலை செய்யக்கூடிய Python built-in function.
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Intermediate
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Definition
String Function String மீது வ……
Explanation
General form
function(string) name = "Pyth……
Program
இங்கே
Explanation
ஒரு built-in function. String Method String object-க்கு already available-ஆ……
Explanation
இங்கே: upper() String method.…
Comparison
Function vs method
முதலில் இந்த difference மிகவும் தெளிவாக இரு……
Comparison
Difference
Concept
Important string concept
Python String immutable. அதனால் பெரும்பாலான String methods……
Explanation
Example
text = "python" text.upper()…
ஏன்? upper() original text-ஐ மாற்றவில்லை……
Algorithm
1. len()…
Definition
len() ஒரு String-ல் எத்தனை ch……
Explanation
Example
text = "Python"…
Explanation
P y t h o n Total: 6 characte……
Important
Space கூட ஒரு character.…
Explanation
Example
text = "Hello World"…
Program
Calculation
Algorithm
1. str()…
str() ஒரு value-ஐ String repr……
Explanation
Syntax
str(value)…
Program
Example
x முதலில் Integer. str(x) பிற……
Algorithm
1. type()…
type() variable அல்லது object……
Explanation
Example
text = "Python"…
Algorithm
1. max()…
String-ல் உள்ள characters-ல் Unicod……
Explanation
Example
text = "abc"…
இதற்கு alphabetical order மட்டும் காரணம் என்று நினைக……
Algorithm
1. min()…
String-ல் minimum character-ஐ……
Explanation
Example
text = "abc"…
Algorithm
1. sorted()…
String characters-ஐ sorted or……
Important
sorted() String return செய்யா……
Explanation
Example
text = "python"…
Algorithm
1. ord()…
ஒரு character-ன் Unicode code……
Program
Example
Program
Example
Algorithm
1. chr()…
ord()-க்கு opposite. Unicode numb……
Program
Example
Program
Example
Comparison
Ord vs chr
Program
Example
String methods-ஐ category-wise படித்தால் எளிதாக நினைவில் இருக்கும். Major categories: Case conversion methods……
Algorithm
1. upper()…
String characters அனைத்தையும் ……
Explanation
Syntax
string.upper() text = "python"…
Algorithm
1. lower()…
String characters அனைத்தையும்……
Explanation
Example
text = "PYTHON"…
Algorithm
1. capitalize()…
String-ன் முதல் character-ஐ upperca……
Explanation
Example
text = "python PROGRAMMING"…
Important
capitalize() எல்லா words-ன் first letter-ஐ uppercase ……
Important
1. title()…
Important
ஒவ்வொரு word-ன் beginning cha……
Explanation
Example
text = "python programming la……
Algorithm
1. swapcase()…
Uppercase-ஐ lowercase ஆகவும்,……
Explanation
Example
text = "PyThOn"…
Algorithm
1. casefold()…
casefold() aggressive lowercase c……
Explanation
Example
text = "PYTHON"…
Simple English strings-ல் lower() மற்றும் casefold() si……
Comparison
Case methods comparison
Comparison
1. find()…
Comparison
String-ல் ஒரு substring எங்கு fir……
Explanation
Syntax
string.find(value) text = "Py……
Explanation
Find with substring
text = "Python Programming" p……
Explanation
When value not found
text = "Python" print(text.fi……
Very important: find() substring க……
Algorithm
1. index()…
index() மற்றும் find() simila……
Explanation
Example
text = "Python"…
Comparison
Find vs index
Main difference: Substring not found என்ற……
Explanation
Example
text = "Python"…
Program
But
Common Mistake
Error
ValueError: substring not fou……
Common Mistake
1. rfind()…
Common Mistake
rfind() right side-லிருந்து search co……
Explanation
Example
text = "banana"…
Index: b a n a n a 0 1 2 3 4 ……
Algorithm
1. rindex()…
Last occurrence index return ……
Explanation
Example
text = "banana"…
Algorithm
1. count()…
ஒரு substring எத்தனை முறை occ……
Explanation
Example
text = "banana"…
Important
Count important
text = "aaaa" print(text.coun……
இந்த methods mostly Boolean v……
Algorithm
1. isalpha()…
String-ல் alphabetic characte……
Explanation
Example
text = "Python"…
But: text = "Python3"…
ஏனெனில் 3 number.…
Algorithm
1. isdigit()…
Digits மட்டும் உள்ளதா என்று c……
Explanation
Example
text = "12345"…
But: text = "123A"…
Algorithm
1. isalnum()…
Alphabet அல்லது Number characters ம……
Explanation
Example
text = "Python123"…
But: text = "Python 123"…
Reason: Space உள்ளது.…
Algorithm
1. isspace()…
Whitespace characters மட்டும்……
Explanation
Example
text = " "…
Algorithm
1. islower()…
String-ல் உள்ள cased letters ……
Explanation
Example
text = "python"…
Algorithm
1. isupper()…
Cased letters அனைத்தும் upper……
Explanation
Example
text = "PYTHON"…
Algorithm
1. istitle()…
String title case format-ல் இ……
Explanation
Example
text = "Python Programming"…
Algorithm
1. isdecimal()…
String decimal characters மட்……
Explanation
Example
text = "123"…
Algorithm
1. isnumeric()…
Numeric characters உள்ளதா என்……
Explanation
Example
text = "123"…
Comparison
Isdecimal vs isdigit vs isnumeric
Basic ASCII numbers-க்கு: text = "123" இந்த மூன்றும் பொதுவாக: True return செய்யும். Conceptual……
Comparison
1. isidentifier()…
Comparison
ஒரு String valid Python identi……
Explanation
Example
name = "student_name"…
But: name = "2student"…
Important
isidentifier() syntax validit……
Program
Example
for keyword ஆனாலும் identifier lex……
Algorithm
1. isprintable()…
String printable characters ம……
Explanation
Example
text = "Python 123"…
Algorithm
1. isascii()…
String-ல் உள்ள characters ASC……
Explanation
Example
text = "Python"…
Algorithm
1. strip()…
Beginning மற்றும் ending-ல் உ……
Explanation
Example
text = " Python "…
Middle space remove ஆகாது.…
Explanation
Example
text = " Python Programming "…
Algorithm
1. lstrip()…
Left side whitespace remove ச……
Explanation
Example
text = " Python "…
Explanation
Result conceptually: Python R……
List
1. rstrip()…
Explanation
Right side whitespace remove ……
Explanation
Left spaces remain.…
Explanation
Strip with characters
strip() spaces மட்டும் அல்ல. Specified ch……
Concept
Important strip concept
strip("abc") exact substring "abc"-ஐ remove செய்யும் என்று நின……
Explanation
Example
text = "abcPythoncab"…
ஒரு substring-ஐ வேறு substrin……
Explanation
Syntax
string.replace(old, new) text……
Explanation
Immutability connection
text = "Java" text.replace("J……
Program
Correct
Explanation
Replace count
Third argument கொடுக்கலாம். r……
First two occurrences மட்டும் r……
Algorithm
1. split()…
ஒரு String-ஐ multiple parts-ஆ……
Explanation
Example
text = "Python Java C"…
Important
split() return type: List Str……
Explanation
Split with separator
text = "Python,Java,C" print(……
Comma separator-ஆ use செய்யப்……
Algorithm
1. rsplit()…
Right side-லிருந்து split ope……
Explanation
Example
text = "a-b-c"…
Algorithm
1. splitlines()…
Multiple lines-ஐ List of line……
Explanation
Example
text = "Python\nJava\nC"…
Algorithm
1. partition()…
ஒரு separator அடிப்படையில் St……
Explanation
Syntax
string.partition(separator)…
Program
Example
Important
partition() Tuple return செய்……
Output
Result
Algorithm
1. rpartition()…
Last occurrence separator அடி……
Explanation
Example
text = "a-b-c"…
Comparison
Split vs partition
Comparison
CATEGORY 7: JOIN METHOD join() Multi……
Explanation
Syntax
separator.join(iterable) இந்த syntax ஆரம்பத்தில் கொஞ……
Flow
Join flow
words = ["Python", "Java", "C……
Output
Result
Explanation
Join with comma
words = ["Python", "Java", "C……
Common Mistake
Common error in join
values = [10, 20, 30] print(",".join(values)) Error வரும். ……
Algorithm
1. startswith()…
String குறிப்பிட்ட text-ஆ sta……
Explanation
Example
text = "Python Programming"…
Algorithm
1. endswith()…
String குறிப்பிட்ட text-ஆ end……
Explanation
Example
file = "notes.pdf"…
Real-time use: File extension……
Algorithm
1. center()…
String-ஐ specified width-ல் c……
Explanation
Example
text = "Python"…
Explanation
Conceptual result: Python…
List
1. ljust()…
Explanation
Left align செய்யும். text = "……
List
1. rjust()…
Explanation
Right align செய்யும். text = ……
Explanation
Fill character
text = "Python" print(text.ce……
Algorithm
1. zfill()…
String-ன் left side-ல் zeros ……
Explanation
Example
text = "25"…
Useful: 001 002 003 போன்ற fixed-widt……
Algorithm
1. removeprefix()…
Specific prefix இருந்தால் அதை……
Explanation
Example
text = "Mr.Ravi"…
Prefix இல்லை என்றால் original……
Algorithm
1. removesuffix()…
Specific suffix இருந்தால் rem……
Explanation
Example
file = "notes.pdf"…
Comparison
Remove prefix vs lstrip
முக்கிய difference. removeprefix() Exact prefix remove செய்யும். lstrip() c……
Comparison
1. format()…
Comparison
Values-ஐ String உள்ளே insert ……
Program
Example
Explanation
text = "My name is {} and I a……
Explanation
Positional format
text = "{0} learns {1}".forma……
Explanation
Named format
text = "{name} learns {course}"……
Explanation
F-string
Modern Python-ல் f-string மிக……
Program
Example
Comparison
Format method vs f-string
Format method: "Name: {}".format(name) F-string: f"Name: {……
Comparison
1. maketrans()…
Comparison
Character translation mapping……
Comparison
1. translate()…
Comparison
Mapping அடிப்படையில் characte……
Program
Example
Explanation
text = "abc"…
Mapping: a -> 1 b -> 2 c -> 3…
Explanation
Encode method
encode() String-ஐ bytes repre……
Default encoding பொதுவாக UTF-……
Explanation
Expandtabs method
Tabs-ஐ spaces-ஆ expand செய்யு……
Explanation
Tab stops அடிப்படையில் spacin……
Explanation
String methods return types
இது exam-க்கு மிகவும் முக்கிய……
Explanation
text = " Python Programming "…
Explanation
text.upper() New uppercase String return செய்கிறது. text.lower() New lowercase String return செய்கிறது. text.……
Real Life Example
Real-time example 1: username validation
username = "student369" if usern……
Real Life Example
Real-time example 2: file type
filename = "notes.pdf" if fil……
Real Life Example
Real-time example 3: search
message = "Learn Python Program……
Important
Note
in என்பது String method அல்ல.……
Input
Real-time example 4: clean input
User input clean செய்ய strip(……
Real Life Example
Real-time example 5: csv-like data
data = "101,Ravi,Computer Sci……
Explanation
Method chaining
String methods ஒன்றன் result மீது இன……
Flow: Original " python programming "……
Explanation
Multiple method chaining
text = " python programming " result =……
Flow: strip() python programming ……
Important
Method chaining works because one method returns an object on w……
Explanation
Example
text.find("P") returns an Integer. So: text……
Common Mistake
Common error 1
Incorrect: text = "python" text.upper() print(t……
Common Mistake
Common error 2
Incorrect: text = "Python" print(text.find()……
Common Mistake
Common error 3
text = "Python" print(text.in……
Common Mistake
Error
ValueError Safer search where……
Common Mistake
Common error 4
numbers = [1, 2, 3] "-".join(……
Common Mistake
Error.
Because items must be strings. Corr……
Common Mistake
Common error 5
Confusing: split() and: join()…
Remember
split One String to many part……
Comparison
Comparison: split vs join
Split: text = "A B C" print(t……
Join: data = ['A', 'B', 'C']…
Memory: String -> List split(……
Comparison
Comparison: find vs count
Definition
Meaning
First occurrence location. co……
Definition
Meaning
Total occurrences.…
Comparison
Comparison: upper vs isupper
upper() converts. text.upper() returns a String. isupper……
Comparison
Comparison: alpha, digit, alnum
Given: "Python" isalpha() -> True isdigit() -> False isalnum() -> True Given: "123" isalpha() -> False isdig……
Memory Trick
Case conversion: upper lower capitalize title swapcase Searching: find index rfind rindex cou……
TRB Point
Important TRB facts: Python String is immutable. len() is a built-in function. upper() is a String method. fi……
Interview Point
Question
What is the difference between a function and a method in Python? Answer: A function is ca……
Interview Point
Question
Does replace() modify a String? Answer: No. Strings……
Interview Point
Question
Difference between find() and index()? Answer: Bot……
Interview Point
Question
Difference between split() and join()? Answer: split() converts one S……
MCQ
What is the output? text = "p……
MCQ
Which one is a built-in funct……
MCQ
What does find() return when ……
MCQ
What happens if index() canno……
MCQ
What is the return type of sp……
MCQ
What is the output? text = "P……
Mcq 7
What is the output? text = "Python 123" print(t……
Mcq 8
What is the output? text = "b……
Mcq 9
What is the output? text = "P……
Mcq 10
What is the output? text = "not……
MCQ
Which method removes whitespa……
MCQ
Which method combines multipl……
Practice
Given: text = " Python Programming " Find the output: print(text.strip()) print(text.upper()) print(text.lowe……
Table
Important complete table
Summary
String Functions and Methods are used to process String data. Function example: len(text) Method example: tex……
Explanation
Short description
String functions and methods are Python operations used to inspect, search, validate, clean, transform, split……
Text size
Theme
Contents
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