Python进阶教程(一)

def test_args_kwargs(name,*args):
    print("frist arg: ",name)
    for arg in args:
        print("another arg through *argv: ",arg)

test_args_kwargs("brian","eric","rose")
#输出为
frist arg:  brian
another arg through *argv:  eric
another arg through *argv:  rose

names=("brian","eric","rose")
test_args_kwargs(*names)
frist arg:  brian
another arg through *argv:  eric
another arg through *argv:  rose

def greet_me(**args):
    for key,value in args.items():
        print("{0}=={1}".format(key,value))

greet_me(name="brian",age=20,sex="男")
#输出为
name==brian
age==20
sex==男

person = {"name":"brian","age":20,"sex":"男"}
greet_me(**person)
#输出为
name==brian
age==20
sex==男

import someclass

def get_info(self,*args):
	return "Test Data"
someclass.get_info=get_info

python -m pdb test.py

import pdb
def method(*args,**kwargv):
	pdb.set_trace()
	...
method(name="sasa")

def fibon(n):
    a=b=1
    for i in range(n):
        yield a
        a,b=b,a+b

for i in fibon(3):
    print(i)
#输出为
1
1
2
#通过next方法来进行获取生成器的下一个迭代
gen_fibon = fibon(3)
print(next(gen_fibon))
print(next(gen_fibon))
print(next(gen_fibon))
#输出结果为
1
1
2
#如果我们再进行下一个迭代时，会出现Exception，这说明我们的迭代已经完成，生成器已经没有再生成Python对象。
print(next(gen_fibon))
---------------------------------------------------------------------------
StopIteration                             Traceback (most recent call last)
<ipython-input-18-5f779bae9fed> in <module>()
----> 1 next(gen_fibon)

StopIteration:

name="brian"
next(name)
#输出结果为，告诉我们python的str了O型不是一个迭代器，那么就无法进行迭代。所以我们需要将str对象模型变成可迭代的python对象数据模型，只需要通过iter(object)方法即可。
TypeError: 'str' object is not an iterator
#代码修改
iter_name = iter(name)
next(iter_name)

temp=[2,7,14,18]
list(map(lambda x: x**2,temp))
#输出结果为：
[4, 49, 196, 324]

def add(x):
    return x+x

def multiply(x):
    return x*x
funcs=(add,multiply)

for i in range(5):
    print(list(map(lambda func:func(i),funcs)))
#输出为
[0, 0]
[2, 1]
[4, 4]
[6, 9]
[8, 16]

nums=range(-5,5)
less_than_zero=list(filter(lambda x:x<0,nums))
#输出为
[-5, -4, -3, -2, -1]

list(i for i in nums if i<0)
#输出结果为同样的

from functools import reduce
print(reduce(lambda x,y:x+y,(2,3,4,5)))
##输出为
14

str_nums=('a','a','b','c','c','c','d','e','f')
duplicates=set([x for x in str_nums if str_nums.count(x)>1])
print(duplicates)
{'a', 'c'}
当然你也可以使用collection的Counter去处理
from collections import Counter
print(Counter(str_nums))
##输出为
Counter({'a': 2, 'b': 1, 'c': 3, 'd': 1, 'e': 1, 'f': 1})

colors=set({'red','yellow','green'})
input_colors=set({'red','blue'})
#交集API
print(input_colors.intersection(colors))
#输出
{'red'}
#差集API
print(input_colors.difference(colors))
#输出
{'blue'}
#并集API
print(input_colors.union(colors))
#输出
{'blue', 'green', 'red', 'yellow'}

flag = True
print("Brian" if flag else "Not Brian")
#输出
Brian