Chapter 5: Sequence Data Types — List, Tuple, Dictionary, Set

name = "PYTHON"
print(name[0])    # P (pehla)
print(name[3])    # H (chautha)
print(name[-1])   # N (aakhri)
print(name[-3])   # T (peeche se teesra)

text = "PYTHON"
print(text[1:4])    # YTH  (index 1,2,3)
print(text[:3])     # PYT  (shuru se index 2 tak)
print(text[2:])     # THON (index 2 se aakhir tak)
print(text[::2])    # PTO  (har 2nd character)
print(text[::-1])   # NOHTYP (poori ulti!)

s = "python programming"
print(s.upper())
print(s.title())
print(s.capitalize())

name = "   Aditya   "
print("[" + name + "]")           # spaces ke saath
print("[" + name.strip() + "]")   # saaf ho gaya

sentence = "Python is fun"
words = sentence.split()          # space se todna
print(words)

joined = "-".join(words)          # "-" se wapas jodna
print(joined)

csv_line = "Ravi,20,Lucknow"
fields = csv_line.split(",")
print(fields)

msg = "I like Java. Java is good."
print(msg.replace("Java", "Python"))   # sab jagah badla
print(msg.find("Java"))                 # pehli baar kahan mila
print(msg.count("Java"))                # kitni baar aaya

filename = "report.pdf"
print(filename.startswith("report"))   # True
print(filename.endswith(".pdf"))       # True

print("Python3".isalpha())    # False - '3' digit hai
print("12345".isdigit())      # True
print("Python3".isalnum())    # True - letters+digits dono chalte hain

empty = []
numbers = [1, 2, 3, 4]
mixed = [10, "Python", 3.14, True]     # kai types ek saath!
nested = [[1, 2], [3, 4]]               # list ke andar list

nums = [10, 20, 30]
nums[1] = 99          # update — index se
nums.append(40)       # end me add
nums.insert(1, 15)    # position 1 par insert
print(nums)

nums.remove(99)       # value se hataya
nums.pop()            # aakhri element hataya
print(nums)

a = [1, 2, 3]
b = [1, 2, 3]

a.append([4, 5])    # POORI list ek hi element ban kar judi
b.extend([4, 5])    # dono elements ALAG-ALAG jude

print("append:", a)
print("extend:", b)

nums = [10, 20, 30, 20, 40, 20]
print(nums.count(20))    # 20 kitni baar hai
print(nums.index(30))    # 30 ki pehli index

safe_copy = nums.copy()
safe_copy.append(99)
print("Original:", nums)      # sanrakshit rahi!
print("Copy:", safe_copy)

marks = [78, 92, 65, 88, 55]
marks.sort()
print("Sorted:", marks)
print("Length:", len(marks))
print("Max:", max(marks), "| Min:", min(marks))
print("Average:", sum(marks) / len(marks))

nums = [1, 2, 3, 4, 5]
squares = [n * n for n in nums]           # har n ka square
evens = [n for n in nums if n % 2 == 0]   # sirf even
print(squares)
print(evens)

t1 = (1, 2, 3)
t2 = (10, "Python", 3.14)
single = (5,)       # COMMA zaroori hai! bina comma yah int hai
not_tuple = (5)     # yah sirf int 5 hai, tuple nahi!
print(type(single), type(not_tuple))

marks = (78, 92, 78, 65, 78, 88)
print(marks.count(78))    # 78 kitni baar hai
print(marks.index(92))    # 92 ki pehli index

student = ("Aditya", 20, "Lucknow")
name, age, city = student      # unpacking!
print(f"{name} rehte hain {city} me, age {age}")

student = {"name": "Amit", "age": 20, "course": "Python"}
print(student["name"])       # direct access
print(student.get("age"))    # safe access (error nahi dega)
print(student.get("city", "N/A"))   # default value agar key nahi mili

d = {"name": "Amit", "age": 20}
d["course"] = "Python"    # naya key-value add
d["age"] = 21              # existing update
print(d)
d.pop("age")               # key hataya
print(d)

student = {"name": "Amit", "age": 20, "course": "Python"}
print(list(student.keys()))
print(list(student.values()))

d1 = {"name": "Amit", "age": 20}
d2 = {"age": 21, "city": "Lucknow"}   # age common hai
d1.update(d2)
print(d1)

d = {"name": "Amit"}
d.setdefault("age", 18)     # "age" nahi thi -> 18 daal di
d.setdefault("name", 99)    # "name" pehle se hai -> nahi badli
print(d)

d.popitem()                  # aakhri jodi hatai
print(d)

nums = [1, 2, 2, 3, 3, 3, 4]
unique = set(nums)
print(unique)

empty = set()   # NOTE: {} khaali dictionary hai, set nahi!

A = {1, 2, 3, 4}
B = {3, 4, 5, 6}
print("Union      :", A | B)   # sab kuch dono se
print("Intersection:", A & B)  # sirf common
print("Difference :", A - B)   # A me hai, B me nahi
print("Symmetric  :", A ^ B)   # dono me alag-alag jo hai

fruits = {"apple", "mango"}
fruits.add("banana")
print(fruits)

fruits.discard("grape")   # grape hai hi nahi — koi error nahi!
print("discard() ke baad bhi safe:", fruits)

# fruits.remove("grape")  # yah ERROR degi — KeyError!

A = {1, 2, 3}
B = {2, 3, 4}

print(A.union(B))          # same as A | B
print(A.intersection(B))   # same as A & B
print(A.difference(B))     # same as A - B

nums = [10, 20, 30]
print("List id before:", id(nums))
nums.append(40)
print("List id after :", id(nums))    # SAME

text = "Python"
print("Str id before:", id(text))
text = text + "3"
print("Str id after :", id(text))     # ALAG

t = (1, [2, 3], 4)
t[1].append(99)      # tuple ka element BADLA nahi, list ke ANDAR add hua
print(t)
# t[0] = 100         # yah error dega — tuple ke direct elements immutable hain

lst = [10, 20, 30, 40, 50]
print(lst[-2])
print(lst[1:-1])

a = [1, 2, 3]
b = a
b.append(4)
print(a)

t = (10)
print(type(t))

d = {"a": 1, "b": 2}
print(d.get("c"))
print(d.get("c", "not found"))

s = {1, 2, 2, 3, 3, 3}
print(len(s))

a = [1, 2, 3]
b = a[:]           # slice se copy
b.append(4)
print(a)
print(b)

matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
print(matrix[1][2])
print(matrix[2][0])

d = {"a": 1, "b": 2, "a": 3}
print(d)

A = {1, 2, 3}
B = {2, 3, 4}
print(A & B)
print(A - B)
print(A ^ B)

s = "PROGRAMMING"
print(s[2:8:2])

fruits = ["apple", "mango", "banana"]
print("mango" in fruits)
print("grape" not in fruits)

t = (1, 2, 3)
t[0] = 100

marks = [67, 89, 45, 92, 78, 55]
print("Maximum:", max(marks))
print("Minimum:", min(marks))
print("Mean:", sum(marks) / len(marks))

nums = [23, 45, 12, 67, 34, 89]
target = int(input("Kya dhoondhna hai: "))
found = False
for i in range(len(nums)):
    if nums[i] == target:
        print(f"Mila! Index {i} par")
        found = True
        break
if not found:
    print("Nahi mila")

text = "banana"
freq = {}
for ch in text:
    freq[ch] = freq.get(ch, 0) + 1
print(freq)

marks = {"Hindi": 85, "Maths": 92, "Science": 78, "English": 88}
total = sum(marks.values())
percent = total / len(marks)
print(f"Total = {total}")
print(f"Percentage = {percent}%")
best = max(marks, key=marks.get)
print(f"Best subject: {best}")

nums = [5, 2, 8, 2, 5, 9, 8, 1]
unique = list(set(nums))
print("Original:", nums)
print("Unique  :", unique)

science_club = {"Amit", "Priya", "Rahul", "Neha"}
sports_club = {"Priya", "Neha", "Karan"}
both = science_club & sports_club
print("Dono clubs me:", both)

nums = [1, 2, 3, 4, 5]
k = 2   # kitna rotate karna hai
rotated = nums[k:] + nums[:k]
print("Original:", nums)
print("Rotated :", rotated)

sentence = "python is easy python is powerful python rocks"
words = sentence.split()
count = {}
for w in words:
    count[w] = count.get(w, 0) + 1
print(count)