Hello Python 教程1

and	exec	not
as	finally	or
assert	for	pass
break	from	print
class	global	raise
continue	if	return
def	import	try
del	in	while
elif	is	with
else	lambda	yield
except	

if True:
   print ("True")

else:
   print ("False")

#如果要在当前语句换行直接用\
total = item_one + \
    item_two + \
    item_three

import sys
print(sys.version) #查看系统版本

print('helloworld   -0');print('helloworld   -1')
print("helloworld   -2")
print("""helloworld   -3

    End .

""",end = ">>")

print("<<")

#Output:
#3.6.1 (v3.6.1:69c0db5050, Mar 21 2017, 01:21:04) 
#[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)]
#helloworld   -0
#helloworld   -1
#helloworld   -2
#helloworld   -3
#    End .
#>><<

dic = {1:"one",2:"two"} #定义字典
print(dic[1])  #取值

print("%d < %s" % (len(dic),"length")) #格式化字符串
del dic[1]   #删除一个key-value
print(len(dic)) #检测字典长度

#!/usr/bin/python3

str = 'HelloWorld!'

print (str)          # Prints complete string
print (str[0])       # Prints first character of the string
print (str[2:5])     # Prints characters starting from 3rd to 5th
print (str[2:])      # Prints string starting from 3rd character
print (str * 2)      # Prints string two times
print (str + "TEST") # Prints concatenated string

#HelloWorld!
#H
#llo
#lloWorld!
#HelloWorld!HelloWorld!
#HelloWorld!TEST

a, b, c, d = 20, 5.5, True, 4+3j
print(type(a), type(b), type(c), type(d))
# <class 'int'> <class 'float'> <class 'bool'> <class 'complex'>

print(isinstance(a, int)) #True

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

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

#('abcd', 786, 2.23, 'john', 70.2)
#abcd
#(786, 2.23)
#(2.23, 'john', 70.2)
#(123, 'john', 123, 'john')
#('abcd', 786, 2.23, 'john', 70.2, 123, 'john')

#!/usr/bin/python

print 'abc', -4.24e93, 18+6.6j, 'xyz';
x, y = 1, 2;
print "Value of x , y : ", x,y;

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 dictionary
print (tinydict.keys())   # Prints all the keys
print (tinydict.values()) # Prints all the values
#This is one
#This is two
#{'name': 'john', 'code': 6734, 'dept': 'sales'}
#dict_keys(['name', 'code', 'dept'])
#dict_values(['john', 6734, 'sales'])

a = ["a","b","c",""]

for item  in a:
  if item == "" :
     print("The Item is Empty")
  else:       
    print(item)
print("over")
#a
#b 
#c
#The Item is Empty
#over

list = [1,2,3,4]
it = iter(list) # this builds an iterator object
print (next(it)) #prints next available element in iterator
Iterator object can be traversed using regular for statement
!usr/bin/python3
for x in it:
   print (x, end=" ")
or using next() function
while True:
   try:
      print (next(it))
   except StopIteration:
      sys.exit() #you have to import sys module for this

def functionA(content,*args):
    print(content)
    for var in args:
        print (var)
    return content

functionA(1,2,3,4,5,6)

sum = lambda arg1, arg2:arg1+arg2

print("%d %s" % (sum(2,3), " <<<"))

try:
    fh = open("testfile", "w")
    try:
        fh.write("这是一个测试文件，用于测试异常!!")
    finally:
        print "关闭文件"
        fh.close()
except IOError:
    print "Error: 没有找到文件或读取文件失败"