Comprehensive Guide to Python Built‑in Functions (68 Functions)

Python provides 68 built‑in functions (as of version 3.6.2) such as print , input , abs , len , etc., which can be used directly without importing modules.

The functions are grouped into twelve thematic groups: numeric‑related (data types, base conversion, arithmetic), data‑structure‑related (sequences, collections, related utilities), scope‑related, iterator‑generator‑related, string execution, input‑output, memory‑related, file‑operation, module‑related, help, callable, and attribute‑inspection.

Numeric‑related examples show base conversion and arithmetic:

<code>print(bin(10))   # 二进制:0b1010
print(hex(10))   # 十六进制:0xa
print(oct(10))   # 八进制:0o12
print(abs(-2))   # 绝对值:2
print(divmod(20,3))  # (6, 2)
print(round(4.51))   # 5
print(pow(10,2,3))   # 1 (10² mod 3)
print(sum([1,2,3,4,5,6,7,8,9,10]))   # 55
print(min(5,3,9,12,7,2))   # 2
print(max(7,3,15,9,4,13))   # 15</code>

Data‑structure examples demonstrate converting iterables, reversing, slicing, and string conversion:

<code>print(list((1,2,3,4,5,6)))   # [1, 2, 3, 4, 5, 6]
print(tuple([1,2,3,4,5,6]))   # (1, 2, 3, 4, 5, 6)
lst = "你好啊"
it = reversed(lst)
print(list(it))   # ['啊', '好', '你']
lst = [1,2,3,4,5,6,7]
print(lst[1:3:1])   # [2, 3]
s = slice(1,3,1)
print(lst[s])   # [2, 3]
print(str(123) + '456')   # 123456
print(format('hello world!', '^20'))   # centered
print(format('hello world!', '<20'))   # left‑aligned
print(format('hello world!', '>20'))   # right‑aligned</code>

Utility functions such as len , sorted , enumerate , all , any , zip , filter , and map are described with usage examples:

<code>lst = [5,7,6,12,1,13,9,18,5]
lst.sort()
print(lst)   # [1, 5, 5, 6, 7, 9, 12, 13, 18]
print(sorted(lst, reverse=True))   # [18, 13, 12, 9, 7, 6, 5, 5, 1]
print(sorted(['one','two','three','four','five','six'], key=len))   # ['one','two','six','four','five','three']
for index, el in enumerate(['one','two','three','four','five'], 1):
    print(index, el)
print(all([1,'hello',True,9]))   # True
print(any([0,0,0,False,1,'good']))   # True
for el in zip([1,2,3,4,5,6], ['a','b','c','d','e','f'], ['X','Y','Z','W','U','V']):
    print(el)
print(list(filter(lambda i: i%2==1, [1,2,3,4,5,6,7,8,9])))   # [1,3,5,7,9]
print(list(map(lambda i: i, [1,2,3,4,5,6,7])))   # [1,2,3,4,5,6,7]</code>

Scope inspection uses locals() and globals() :

<code>def func():
    a = 10
    print(locals())   # {'a': 10}
    print(globals())   # {...}
    print("今天内容很多")
func()</code>

Iterator generation uses range() , iter() , and next() :

<code>for i in range(15, -1, -5):
    print(i)   # 15 10 5 0
lst = [1,2,3,4,5]
it = iter(lst)
print(next(it))   # 1
print(next(it))   # 2</code>

String execution functions eval , exec , and compile are shown:

<code>s1 = input("请输入a+b:")   # e.g., 8+9
print(eval(s1))   # 17
s2 = "for i in range(5): print(i)"
exec(s2)   # prints 0‑4
code = "5+6+7"
print(eval(compile(code, "", mode="eval")))   # 18</code>

Input‑output functions print() and input() are covered:

<code>print("hello", "world", sep="*", end="@")   # hello*world@</code>

Memory‑related helpers hash() and id() demonstrate obtaining hash values and object addresses:

<code>s = 'alex'
print(hash(s))   # e.g., -168324845050430382
print(id(s))   # e.g., 2278345368944</code>

File handling uses open() :

<code>f = open('file', mode='r', encoding='utf-8')
content = f.read()
f.close()</code>

Dynamic module loading uses __import__() :

<code>name = input("请输入你要导入的模块:")
__import__(name)</code>

Help utilities help() , callability check callable() , and attribute inspection dir() are demonstrated:

<code>print(help(str))
print(callable(10))   # False
print(callable(lambda x: x))   # True
print(dir(tuple))   # list of tuple methods</code>