tpl = "i am %s" % "alex"tpl = "i am %s age %d" % ("alex", 18)tpl = "i am %(name)s age %(age)d" % {"name": "alex", "age": 18}tpl = "percent %.2f" % 99.97623tpl = "i am %(pp).2f" % {"pp": 123.425556, }tpl = "i am %.2f %%" % {"pp": 123.425556, }

tpl = "i am {}, age {}, {}".format("seven", 18, 'alex')tpl = "i am {}, age {}, {}".format(*["seven", 18, 'alex'])tpl = "i am {0}, age {1}, really {0}".format("seven", 18)tpl = "i am {0}, age {1}, really {0}".format(*["seven", 18])tpl = "i am {name}, age {age}, really {name}".format(name="seven", age=18)tpl = "i am {name}, age {age}, really {name}".format(**{"name": "seven", "age": 18})tpl = "i am {0[0]}, age {0[1]}, really {0[2]}".format([1, 2, 3], [11, 22, 33])tpl = "i am {:s}, age {:d}, money {:f}".format("seven", 18, 88888.1)tpl = "i am {:s}, age {:d}".format(*["seven", 18])tpl = "i am {name:s}, age {age:d}".format(name="seven", age=18)tpl = "i am {name:s}, age {age:d}".format(**{"name": "seven", "age": 18})tpl = "numbers: {:b},{:o},{:d},{:x},{:X}, {:%}".format(15, 15, 15, 15, 15, 15.87623, 2)tpl = "numbers: {:b},{:o},{:d},{:x},{:X}, {:%}".format(15, 15, 15, 15, 15, 15.87623, 2)tpl = "numbers: {0:b},{0:o},{0:d},{0:x},{0:X}, {0:%}".format(15)tpl = "numbers: {num:b},{num:o},{num:d},{num:x},{num:X}, {num:%}".format(num=15)

#!/usr/bin/env python
# -*-coding:utf-8 -*-"""我是注释.........
"""print(__doc__)#   我是注释.........

print(__file__)# F:/PycharmProjects/Python/W4/Day12/lib/index.py******************************p1 = os.path.dirname(__file__)
p2 = 'lib'
my_dir = os.path.join(p1,p2)
sys.path.append(my_dir)

# ***************************
lib -> common -> index.py# ***************************
s1.pyfrom lib.common import index
print(index.__package__)#lib.common

from lib.common import indexprint(__name__)
print(index.__name__)# __main__
# lib.common.index

　　调用主函数前,先加 if __name__ == '__main__'

# index.pydef f1():print('hello!')if __name__ == '__main__':f1()# 执行index.py 输出hello!********************************
# index2.pyimport index# 执行index2.py 没有输出内容

1.软件管理工具

　　pip3

　　　　1.依赖,先安装 setuptools

　　　　2.pip3 添加到环境变量

　　　　3. pip3 install requests

2.源码安装

　　1.下载代码,安装

　　2.进入文件后, python setup.py install

迭代器和生成器

1、迭代器

迭代器是访问集合元素的一种方式。迭代器对象从集合的第一个元素开始访问，直到所有的元素被访问完结束。迭代器只能往前不会后退，不过这也没什么，因为人们很少在迭代途中往后退。另外，迭代器的一大优点是不要求事先准备好整个迭代过程中所有的元素。迭代器仅仅在迭代到某个元素时才计算该元素，而在这之前或之后，元素可以不存在或者被销毁。这个特点使得它特别适合用于遍历一些巨大的或是无限的集合，比如几个G的文件

特点：

1. 访问者不需要关心迭代器内部的结构，仅需通过next()方法不断去取下一个内容
2. 不能随机访问集合中的某个值 ，只能从头到尾依次访问
3. 访问到一半时不能往回退
4. 便于循环比较大的数据集合，节省内存

>>> a = iter([1,2,3,4,5])
>>> a
<list_iterator object at 0x101402630>
>>> a.__next__()
1
>>> a.__next__()
2
>>> a.__next__()
3
>>> a.__next__()
4
>>> a.__next__()
5
>>> a.__next__()
Traceback (most recent call last):File "<stdin>", line 1, in <module>
StopIteration

2、生成器

一个函数调用时返回一个迭代器，那这个函数就叫做生成器（generator）；如果函数中包含yield语法，那这个函数就会变成生成器；

def func():print(11)yield 1print(22)yield 2print(33)yield 3temp = func()　　# 得到生成器,此时不执行ret = temp .__next__() # 执行上一个yield和  下一个yield中间的代码
print(ret)ret = temp .__next__()
print(ret)

3、实例

a、利用生成器自定义range

def nrange(num):temp = -1while True:temp = temp + 1if temp >= num:returnelse:yield temp

b、利用迭代器访问range

for i in nrange(10):print(i)