Python Base 　　

基本语法

https://www.tutorialspoint.com/python/python_command_line_arguments.htm

0.init

0.1 import function

unap@honap:~/test/tosca$ cat tran/common/utils.py

def add(a, b):
    c = a + b
    return c

unap@honap:~/test/tosca$ cat tran/shell.py
import sys
from tran.common.utils import hhb
#import trans.common.utils as yui

def main(args=None):
    if args is None:
        args = sys.argv[1:]
        print args
        print add(1,2)
        # print yui.add(1,2)


if __name__ == '__main__':
    main()

0.2 import class

unap@honap:~/test/tosca$ cat tran/common/utils.py
class Oper:
    def add(self, a, b):
        c = a + b
        return c

unap@honap:~/test/tosca$ cat tran/shell.py
import sys
from tran.common.utils import Oper

def main(args=None):
    if args is None:
        args = sys.argv[1:]
        print args
		oper1 = Oper()
        print add(1,2)


if __name__ == '__main__':
    main()

0.3 自动执行

add "#!/usr/bin/env python" to hello.py head
$ chmod a+x hello.py
$ hello.py

1.option

1.1 python -m

unap@honap:~/test/tosca/tran$ cat shell.py
import sys

def main(args=None):
    if args is None:
        args = sys.argv[1:]
        print args


if __name__ == '__main__':
    main()


unap@honap:~/test/tosca/tran$ PYTHONPATH=$PYTHONPATH:. python -m shell yui ert
['yui', 'ert']

1.2 python -c

python -c 'import sys, yaml, json; json.dump(yaml.load(sys.stdin), sys.stdout, indent=4)' < openwrt-vnf.yaml

2. loops

2.1 for loops

#!/usr/bin/python

for letter in 'Python':     # First Example
   print 'Current Letter :', letter

fruits = ['banana', 'apple',  'mango']
for fruit in fruits:        # Second Example
   print 'Current fruit :', fruit

print "Good bye!"


>>> names = ['hhb', 'ywh']
>>> for i in range(len(names)):
...     print names[i]
...
hhb
ywh
>>> names.index('ywh')
1

2.2 while loops

#!/usr/bin/python

count = 0
while (count < 9):
   print 'The count is:', count
   count = count + 1

print "Good bye!"

2.3 nested loops

#!/usr/bin/python

i = 2
while(i < 100):
   j = 2
   while(j <= (i/j)):
      if not(i%j): break
      j = j + 1
   if (j > i/j) : print i, " is prime"
   i = i + 1

print "Good bye!"

2.4 Control Statement

break
continue
pass

3. if

x == y      x 等于 y
x < y       x 小于 y
x <= y      x 小于等于 y
x != y      x 不等于 y
x is y      x 和 y 是同一个对象
x is not y  x 和 y 不是同一个对象
x in y      x 是 y 容器(例如：序列)的成员
x not in y  x 不是 y 容器(例如：序列)的成员

3.1 int compare

def letterGrade(score):
    if score >= 90:
        letter = 'A'
    elif score >= 80:
        letter = 'B'
    elif score >= 70:
        letter = 'C'
    elif score >= 60:
        letter = 'D'
    else:
        letter = 'F'
    return letter

3.2 string compare

if(action == "get"):
    resp = requests.get(url, verify=False)
    content = resp.json()

elif(action == "post"):
    headers = {'Content-Type': 'application/json',}
    resp = requests.post(url, headers=headers, data=json.JSONEncoder().encode(request.data), verify=False)
    content = resp.json()

elif (action == "delete"):
    resp = requests.delete(url, verify=False)
    content = resp.json()

4. Variable

4.1 Global Variable

$ cat check_events_log.py

jpgdata=''
def openlogfile():
    global jpgdata
    with open(options.logfile, 'rb') as inf:
        jpgdata = inf.read()

openlogfile()
print jpgdata

4.2 Variable Types

Python has five standard data types −

define variable: var1=10 undefine variable: del var1

分割字符串

	image = "openwrt-image"
    m = re.search(r'^([0-9a-zA-Z]+)-([0-9a-zA-Z]+)$', image)
 	name = m.group(1)

	image="openwrt-image"
	m = image.split('-')
	print m[0]
	'openwrt'

To some extent, lists are similar to arrays in C. One difference between them is that all the items belonging to a list can be of different data type.

#!/usr/bin/python

list = [ 'abcd', 786 , 2.23, 'john', 70.2 ]
tinylist = [123, 'john']

print list          # Prints complete list
print list[0]       # Prints first element of the list
print list[1:3]     # Prints elements starting from 2nd till 3rd 
print list[2:]      # Prints elements starting from 3rd element
print tinylist * 2  # Prints list two times
print list + tinylist # Prints concatenated lists

>>> list1=['we',786]
>>> list2=['op']
>>> list1+list2
['we', 786, 'op']
>>> list1*5
['we', 786, 'we', 786, 'we', 786, 'we', 786, 'we', 786]
>>> 'we' in list1
True
>>> 'we' in list2
False

The main differences between lists and tuples are: Lists are enclosed in brackets ( [ ] ) and their elements and size can be changed, while tuples are enclosed in parentheses ( ( ) ) and cannot be updated. Tuples can be thought of as read-only lists. For example −

#!/usr/bin/python

tuple = ( 'abcd', 786 , 2.23, 'john', 70.2  )
tinytuple = (123, 'john')

print tuple           # Prints complete list
print tuple[0]        # Prints first element of the list
print tuple[1:3]      # Prints elements starting from 2nd till 3rd 
print tuple[2:]       # Prints elements starting from 3rd element
print tinytuple * 2   # Prints list two times
print tuple + tinytuple # Prints concatenated lists

A dictionary key can be almost any Python type, but are usually numbers or strings. Values, on the other hand, can be any arbitrary Python object.

Dictionaries are enclosed by curly braces ({ }) and values can be assigned and accessed using square braces ([]). For example −

#!/usr/bin/python

dict = {}
dict['one'] = "This is one"
dict[2]     = "This is two"

tinydict = {'name': 'john','code':6734, 'dept': 'sales'}


print dict['one']       # Prints value for 'one' key
print dict[2]           # Prints value for 2 key
print tinydict          # Prints complete dictionaryi
print tinydict.keys()   # Prints all the keys
print tinydict.values() # Prints all the values

字典方法：

字典 setdefault() 函数和get() 方法类似, 如果键不存在于字典中，将会添加键并将值设为默认值。

setdefault()方法语法：
dict.setdefault(key, default=None)
参数
key -- 查找的键值。
default -- 键不存在时，设置的默认键值。
返回值
如果字典中包含有给定键，则返回该键对应的值，否则返回为该键设置的值。

netcard = {}	# 二级字典

def set_val(**args):
    x={}		# 一级字典
    ibdf={'bdf:': args['bdf']}
    idriver={'driver:': args['driver']}

    x.update(ibdf)
    x.update(idriver)	
    y={bdf: x}
    netcard.update(y)

def show_all():
    for yu in netcard.keys():
        for k,v in netcard[yu].items():
            print '\033[1;32;40m'+k+'\033[0m'+'='+str(v)
        print "\n"


set_val(driver=driver,bdf=bdf)

show_all()

>>> labels = {'phone':'181', 'addr':'yqf'}
>>> labels['phone']='189'
>>> labels.has_key('ho')
False
>>> labels.get('phone')
'189'

>>> d = {'x':1, 'y':2}
>>> for key in d:
...     print key, 'corresponds to', d[key]
...
y corresponds to 2
x corresponds to 1

>>> for key, value in d.items():
...     print key, value

字典引用

labels['phone']='189'
dict_data["topology_template"]["node_templates"]["VDU1"]["properties"]["image"]

4.3 Data Type Conversion

Sometimes, you may need to perform conversions between the built-in types. To convert between types, you simply use the type name as a function.

There are several built-in functions to perform conversion from one data type to another. These functions return a new object representing the converted value.

int(x [,base]):Converts x to an integer. base specifies the base if x is a string. for example: int(“a”, 16)

float(x):Converts x to a floating-point number.

str(x):Converts object x to a string representation.

repr(x):Converts object x to an expression string.

dict(d):Creates a dictionary. d must be a sequence of (key,value) tuples.

hex(x):Converts an integer to a hexadecimal string.

oct(x):Converts an integer to an octal string.

4.4 进制

>>> 0xAF        # 16进制
175
>>> 010         # 8 进制
8

5.input/output

5.1 获取用户输入

>>> input("The meaning of lif:")
The meaning of life: 42
42

5.2 交互变量值

>>> x, y, z = 1, 2, 3
>>> print x, y, z
1 2 3
>>> x, y = y, x
>>> print x, y, z
2 1 3

5.3 序列解包

>>> scoundrel = {'name':'hhb', 'gf':'ywh'}
>>> key, value = scoundrel.popitem()
>>> print key, value
gf ywh
>>> print scoundrel
{'name': 'hhb'}
>>>

5.class

5.1 private method

$ cat test.py
class Se:

    def __in(self):
        print "Bet you can't see me..."

    def ac(self):
        print "the secret message is:"
        self.__in()

s = Se()
s.ac()
s.__in()


s.__in()
AttributeError: Se instance has no attribute '__in'

5.2 static variable

$ cat selftest.py
class Mc:
    members = 0
    def init(self):
        Mc.members += 1

m1 = Mc()
m1.init()
print Mc.members

m2 = Mc()
m2.init()
print Mc.members

5.3 self variable

class Mc:
    def init(self):
        self.members = 1

m1 = Mc()
m1.init()
print m1.members

m2 = Mc()
m2.init()
print m2.members

5.4 inherit

$ cat inherit.py
#!/usr/bin/python
# Filename: inherit.py

class SchoolMember:
    '''Represents any school member.'''
    def __init__(self, name, age):
        self.name = name
        self.age = age
        print '(Initialized SchoolMember:%s)' % self.name

    def tell(self):
        '''Tell my details.'''
        print 'Name:"%s" Age:"%s"' % (self.name, self.age)

class Teacher(SchoolMember):
    '''Represents a teacher.'''
    def __init__(self, name, age, salary):
        SchoolMember.__init__(self, name, age)
        self.salary = salary
        print'(Initialized Teacher: %s)'% self.name

    def tell(self):
        SchoolMember.tell(self)
        print'Salary: "%d"'% self.salary
	
class Student(SchoolMember):
    '''Represents a student.'''
    def __init__(self, name, age, marks):
        SchoolMember.__init__(self, name, age)
        self.marks = marks
        print'(Initialized Student: %s)'% self.name

    def tell(self):
        SchoolMember.tell(self)
        print'Salary: "%d"'% self.marks

t = Teacher('Mrs.shrividya', 40, 3000)
s = Student('Swaroop', 22, 75)

members = [t, s]
for member in members:
    member.tell()

10.参考资料

10.1 Eclipse 环境搭建

http://lztang1964.blog.163.com/blog/static/187545985201302310814922/ http://www.huqiwen.com/2012/05/01/spring3-mvc-quick-start-1/

10.2 Python工程及学习书籍

http://www.cnblogs.com/realh/archive/2010/10/04/1841907.html

10.3 Python 连ia

https://github.com/openstack/python-novaclient

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