1️⃣ Q: Return the first duplicate in a list.
def first_duplicate(lst):
seen = set()
for x in lst:
if x in seen:
return x
seen.add(x)
return None
print(first_duplicate([3, 1, 3, 4, 2])) # Output: 3
2️⃣ Q: Check whether a number is a palindrome.
def is_pal_num(n):
return str(n) == str(n)[::-1]
print(is_pal_num(121)) # True
print(is_pal_num(123)) # False
3️⃣ Q: Sort a dictionary by values.
def sort_by_value(d):
return dict(sorted(d.items(), key=lambda x: x[1]))
print(sort_by_value({'a': 3, 'b': 1, 'c': 2}))
Output: {'b': 1, 'c': 2, 'a': 3}
4️⃣ Q: Return all prime numbers in a given range.
def primes_upto(n):
primes = []
for num in range(2, n + 1):
for i in range(2, int(num**0.5) + 1):
if num % i == 0:
break
else:
primes.append(num)
return primes
print(primes_upto(10)) # [2, 3, 5, 7]
5️⃣ Q: Convert a list of numbers into a string.
def list_to_string(lst):
return "".join(map(str, lst))
print(list_to_string([1, 2, 3])) # Output: 123
💬 Double Tap ❤️ for Part-12