Lesson 06B - Deep Dive

TUPLE METHODS:
COUNT AUR INDEX

Tuple immutable hai - isliye Python ne isme sirf 2 methods diye hain: count() aur index(). Baaki saare kaam built-in functions se hote hain (len, max, sorted...). Ye page tuple ke dono methods + un 10+ functions ko real examples ke saath cover karta hai - interview aur exam dono ke liye.

WHY: tuple mein sirf 2 methods kyun hain

List mein 10+ methods hain (append, remove, sort...) kyunki list change ho sakti hai. Tuple ek baar banne ke baad fix - isliye add/remove/replace jaise methods ka koi matlab hi nahi. Python tuple ko jaan-boojh kar chhota rakhta hai: chhota object = fast aur safe.

1. count() - kitni baar mila

count(x) batata hai ki value x tuple mein kitni baar aayi hai. Return type: int. Na mile to 0 - error nahi.

marks = (88, 92, 76, 92, 92, 85)

print(marks.count(92))   # 3
print(marks.count(76))   # 1
print(marks.count(100))  # 0 - absent ka count, error nahi

# Use case: exam results mein kitne students ne 92 banaye
toppers = (88, 92, 76, 92, 92, 85)
if toppers.count(92) > 1:
    print("92 wale ek se zyada hain!")

2. index() - kahan mila (pehli jagah)

index(x) value x ki pehli position (0-based index) deta hai. Na mile to ValueError - isliye safe pattern zaroor seekho.

cities = ("Lucknow", "Kanpur", "Varanasi", "Lucknow")

print(cities.index("Kanpur"))    # 1
print(cities.index("Lucknow"))   # 0 - sirf pehli jagah

# Safe pattern 1: pehle check
if "Agra" in cities:
    print(cities.index("Agra"))

# Safe pattern 2: try-except
try:
    print(cities.index("Agra"))
except ValueError:
    print("Agra tuple mein nahi hai")

Important: duplicate ho to index() sirf pehli position dega. Poori list chahiye to [i for i, v in enumerate(t) if v == x] pattern use karo.

3. Built-in functions jo tuples par chalte hain

Ye wahi sawaal hain jo "methods of tuple" naam se exam mein aate hain - answer: methods sirf 2, par functions bahut:

t = (12, 4, 19, 4)

print(len(t))            # 4
print(max(t), min(t))    # 19 4
print(sum(t))            # 39
print(sorted(t))         # [4, 4, 12, 19] - list milegi
print(sorted(t)[-1])     # 19 - sabse bada, one-liner
print(any(t), all(t))    # True True
print(19 in t)           # True

# reverse tuple: sorted ka reverse flag
print(sorted(t, reverse=True))  # [19, 12, 4, 4]

4. Unpacking: tuple ke andar se values nikaalo

# Poora unpack
x, y, z = (10, 20, 30)
print(x, y, z)  # 10 20 30

# Star (*) - extra sab ek list mein
first, *rest = (1, 2, 3, 4)
print(first)  # 1
print(rest)   # [2, 3, 4]

# Swap trick: variables ki values exchange
a, b = 5, 9
a, b = b, a
print(a, b)   # 9 5

# zip se 2 tuples jodo pairs banake
names = ("Aman", "Priya")
scores = (88, 95)
print(list(zip(names, scores)))  # [('Aman', 88), ('Priya', 95)]

# Strings bhi tuple ki tarah unpack hote hain
ch, rest = "Lucknow"
print(ch, rest)  # L ucknow

5. Tuple banana aur badalne ka pattern

# Tuple banane ke tarike
t1 = (1, 2, 3)                 # direct
t2 = tuple([4, 5, 6])          # list se
t3 = tuple("abc")              # string se -> ('a', 'b', 'c')
t4 = ()                        # khali tuple
t5 = (7,)                      # single-element tuple - comma zaroori!

# Badalna ho to: tuple -> list -> change -> tuple
t = (1, 2, 3)
t = tuple(list(t) + [4])       # (1, 2, 3, 4)
print(t)

6. Common mistakes (interview traps)

• (5) tuple nahi hai - number hai! Single element tuple = (5,) - comma zaroori.
• t.sort() error dega - tuple mein sort method hi nahi. sorted(t) use karo (wo list deta hai).
• t.append(4) bhi AttributeError - pehle list(t) banao, badlo, wapas tuple().
• index() na mile par ValueError deta hai - in check ya try-except lagao.
• Tuple mein tuple ho sakta hai (nested) - usse flatten karne ke liye recursion ya itertools.chain chahiye.