參考文獻(xiàn)：廖雪峰老師的官網(wǎng)

1.數(shù)據(jù)類型轉(zhuǎn)換

>>> int('123')

123

>>> int(12.34)

12

>>> float('12.34')

12.34

>>> str(1.23)

'1.23

'>>> str(100)

'100'

>>> bool(1)

True

>>> bool('')

False

int(),bool(),str();

2.定義函數(shù)

# -*- coding: utf-8 -*-

def my_abs(x):

? ? if x >= 0:

? ? ? ? return x

? ? else:

? ? ? ? return -x

print(my_abs(-99))

3.空函數(shù)

def nop():

??? pass

pass語句什么都不做，那有什么用？實際上pass可以用來作為占位符，比如現(xiàn)在還沒想好怎么寫函數(shù)的代碼，就可以先放一個pass，讓代碼能運行起來。

4.可變參數(shù)

>>> def calc(number):

...? ? sum = 0

...? ? for n in number:

...? ? ? ? sum = sum + n * n

...? ? return sum

>>> calc([1,2,3,4])

30

5.關(guān)鍵參數(shù)

def person(name, age, **kw):

??? print('name:', name,'age:', age,'other:', kw)

>>> person('Bob',35, city='Beijing')

name: Bob age:35other: {'city':'Beijing'}

>>> person('Adam',45, gender='M', job='Engineer')

name: Adam age:45other: {'gender':'M','job':'Engineer'}

>>> extra = {'city':'Beijing','job':'Engineer'}

>>> person('Jack',24, **extra)

name: Jack age:24other: {'city':'Beijing','job':'Engineer'}