Common Python Built‑in Functions with Example Code

print() – prints information to the console. print("Hello, World!") len() – returns the length of a collection.

my_list = [1, 2, 3, 4, 5]
print(len(my_list))  # 5

type() – obtains the type of an object.

var = 10
print(type(var))  # <class 'int'>

int(), float(), str() – convert between string, integer and float types.

num_str = "123"
num_int = int(num_str)
print(num_int)  # 123

num_float_str = "123.45"
num_float = float(num_float_str)
print(num_float)  # 123.45

num = 123
num_str_converted = str(num)
print(num_str_converted)  # "123"

list(), tuple(), set() – create or convert to common containers.

my_tuple = (1, 2, 3)
my_list_from_tuple = list(my_tuple)
print(my_list_from_tuple)  # [1, 2, 3]

my_list = [1, 2, 2, 3, 4]
my_set_from_list = set(my_list)
print(my_set_from_list)  # {1, 2, 3, 4}

my_dict = dict([('a', 1), ('b', 2)])
print(my_dict)  # {'a': 1, 'b': 2}

range(), sum(), min(), max() – generate numeric sequences and compute aggregates.

numbers = range(1, 6)
print(sum(numbers))  # 15
print(min(numbers))  # 1
print(max(numbers))  # 5

input() – read user input from the console.

user_input = input("请输入您的名字: ")
print("你好，" + user_input + "!")

round() – round a floating‑point number to a given precision.

rounded_num = round(3.14159, 2)
print(rounded_num)  # 3.14

enumerate() – iterate with index and value.

fruits = ['apple', 'banana', 'cherry']
for index, fruit in enumerate(fruits):
    print(index, fruit)

zip() – iterate over multiple iterables in parallel.

names = ['Alice', 'Bob', 'Charlie']
ages = [24, 30, 22]
for name, age in zip(names, ages):
    print(name, "is", age, "years old.")

sorted() – return a sorted list.

unsorted_list = [3, 1, 4, 1, 5, 9, 2, 6]
sorted_list = sorted(unsorted_list)
print(sorted_list)  # [1, 1, 2, 3, 4, 5, 6, 9]

any(), all() – logical checks over iterables.

bool_list = [True, False, True]
print(any(bool_list))  # True
print(all(bool_list))  # False

bin(), oct(), hex() – convert an integer to binary, octal, or hexadecimal string.

decimal_number = 10
print(bin(decimal_number))  # 0b1010
print(oct(decimal_number))  # 0o12
print(hex(decimal_number))  # 0xA

chr(), ord() – convert between Unicode code points and characters.

char = chr(97)  # 'a'
print(char)  # a

unicode_point = ord('€')
print(unicode_point)  # 8364

help() and dir() – inspect objects and obtain documentation.

print(dir(list))
help(list.append)

input() with type conversion – read and convert user input.

age = int(input("请输入您的年龄: "))
print("您输入的年龄是:", age)

round() for floating‑point precision – another example.

number = 3.14159
rounded = round(number, 3)
print(rounded)  # 3.142

range() in a loop – iterate over a sequence of numbers.

for i in range(5):
    print(i, end=' ')
# Output: 0 1 2 3 4