List, Set और Dictionary Comprehension

prices = [120, 450, 80, 999]

# normal loop
with_gst = []
for p in prices:
    with_gst.append(round(p * 1.18))
print(with_gst)

# list comprehension – same result
with_gst = [round(p * 1.18) for p in prices]
print(with_gst)

marks = {"Asha": 91, "Ravi": 58, "Neha": 76, "Kabir": 34, "Isha": 88}

passed = [name for name, m in marks.items() if m >= 40]
toppers = [name for name, m in marks.items() if m >= 85]
print("Passed :", passed)
print("Toppers:", toppers)

marks = [91, 58, 76, 34, 88]

result = ["Pass" if m >= 40 else "Fail" for m in marks]
grades = ["A" if m >= 85 else "B" if m >= 60 else "C" if m >= 40 else "F" for m in marks]
print(result)
print(grades)

items = ["kaju katli", "ghewar", "rasmalai"]
price = [900, 650, 700]

menu = {name.title(): p for name, p in zip(items, price)}
print(menu)

discounted = {k: round(v * 0.9) for k, v in menu.items() if v > 680}
print(discounted)

# swap keys and values
by_price = {v: k for k, v in menu.items()}
print(by_price[650])

emails = ["riya@gmail.com", "AMAN@yahoo.com", "neha@gmail.com", "aman@yahoo.com"]

domains = {e.split("@")[1].lower() for e in emails}
unique_users = {e.lower() for e in emails}
print(sorted(domains))
print(len(emails), "emails,", len(unique_users), "unique")

sections = [["Asha", "Ravi"], ["Neha"], ["Kabir", "Isha", "Om"]]

# loops are written in the same order as normal nested for-loops
all_students = [s for section in sections for s in section]
print(all_students)

table = [[r * c for c in range(1, 4)] for r in range(1, 4)]
for row in table:
    print(row)

raw = ["  asha sharma ", "RAVI kumar", "", "neha  verma", "  ", "Kabir Singh"]

clean = [" ".join(name.split()).title() for name in raw if name.strip()]
initials = {name: "".join(part[0] for part in name.split()) for name in clean}

print(clean)
print(initials)

import timeit

loop_code = """
result = []
for n in range(10000):
    result.append(n * 2)
"""
comp_code = "result = [n * 2 for n in range(10000)]"

t_loop = timeit.timeit(loop_code, number=300)
t_comp = timeit.timeit(comp_code, number=300)
print("comprehension faster:", t_comp < t_loop)