Python基本语法--语句

# -*- coding: utf-8 -*-
#条件语句
'''
if 判断条件：
    执行语句……
else：
    执行语句……
'''

flag = False
name = 'python'
if name == 'python':         # 判断变量否为'python'
    flag = True              # 条件成立时设置标志为真
    print 'welcome boss'    # 并输出欢迎信息
else:
    print name              # 条件不成立时输出变量名称

'''
if 判断条件1:
    执行语句1……
elif 判断条件2:
    执行语句2……
elif 判断条件3:
    执行语句3……
else:
    执行语句4……
'''

num = 2     
if num == 3:            # 判断num的值
    print 'boss'        
elif num == 2:
    print 'user'
elif num == 1:
    print 'worker'
elif num < 0:           # 值小于零时输出
    print 'error'
else:
    print 'roadman'     # 条件均不成立时输出

num = 9
if num >= 0 and num <= 10:    # 判断值是否在0~10之间
    print 'hello'


num = 10
if num < 0 or num > 10:    # 判断值是否在小于0或大于10
    print 'hello'
else:
    print 'undefine'


num = 8
# 判断值是否在0~5或者10~15之间
if (num >= 0 and num <= 5) or (num >= 10 and num <= 15):    
    print 'hello'
else:
    print 'undefine'


var = 100  
if ( var  == 100 ) : print "变量 var 的值为100" 
print "Good bye!"


#while语句
'''
while 判断条件：
    执行语句……
'''
count = 0
while (count < 9):
   print 'The count is:', count
   count = count + 1

print "Good bye!"

# continue 和 break 用法

i = 1
while i < 10:   
    i += 1
    if i%2 > 0:     # 非双数时跳过输出
        continue
    print i         # 输出双数2、4、6、8、10

i = 1
while 1:            # 循环条件为1必定成立
    print i         # 输出1~10
    i += 1
    if i > 10:     # 当i大于10时跳出循环
        break

#死循环
'''
var = 1
while var == 1 :  # 该条件永远为true，循环将无限执行下去
   num = raw_input("Enter a number  :")
   print "You entered: ", num

print "Good bye!"
'''


#while … else 
count = 0
while count < 5:
   print count, " is  less than 5"
   count = count + 1
else:
   print count, " is not less than 5"

#简单语句组
flag = 1
while (flag): print 'Given flag is really true!';flag=0;
print "Good bye!"

#for语句
'''
for iterating_var in sequence:
   statements(s)
'''
for letter in 'Python':     # 第一个实例
   print '当前字母 :', letter

fruits = ['banana', 'apple',  'mango']
for fruit in fruits:        # 第二个实例
   print '当前水果 :', fruit

print "Good bye!"

#序列索引迭代
fruits = ['banana', 'apple',  'mango']
for index in range(len(fruits)):
   print '当前水果 :', fruits[index]

print "Good bye!"

#for...else
for num in range(10,20):  # 迭代 10 到 20 之间的数字
   for i in range(2,num): # 根据因子迭代
      if num%i == 0:      # 确定第一个因子
         j=num/i          # 计算第二个因子
         print '%d 等于 %d * %d' % (num,i,j)
         break            # 跳出当前循环
   else:                  # 循环的 else 部分
      print num, '是一个质数'

#嵌套循环
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, " 是素数"
   i = i + 1

print "Good bye!"

#break语句
for letter in 'Python':     # First Example
   if letter == 'h':
      break
   print 'Current Letter :', letter
  
var = 10                    # Second Example
while var > 0:              
   print 'Current variable value :', var
   var = var -1
   if var == 5:
      break

print "Good bye!"

#continue语句
for letter in 'Python':     # 第一个实例
   if letter == 'h':
      continue
   print '当前字母 :', letter

var = 10                    # 第二个实例
while var > 0:              
   var = var -1
   if var == 5:
      continue
   print '当前变量值 :', var
print "Good bye!"

#pass语句
# 输出 Python 的每个字母
for letter in 'Python':
   if letter == 'h':
      pass
      print '这是 pass 块'
   print '当前字母 :', letter

print "Good bye!"

#格式字符串
print "My name is %s and weight is %d kg!" % ('Zara', 21) 

#时间与日期
import time;  # This is required to include time module.

ticks = time.time()
print "Number of ticks since 12:00am, January 1, 1970:", ticks

localtime = time.localtime(time.time())
print "Local current time :", localtime

localtime = time.asctime( time.localtime(time.time()) )
print "Local current time :", localtime

import calendar

cal = calendar.month(2008, 1)
print "Here is the calendar:"
print cal;