python 基础之第四天

Posted 2020-10-01

例子1：

打印列表每个元素对应的索引

[[email protected] script]# vim suoyin.py
#!/usr/bin/python
# coding:utf-8

alist = [‘fu‘,‘shan‘,‘hua‘,‘hive‘]

for i in range(len(alist)):
    print ‘%s:%s‘ % (i,alist[i])

检验：
[[email protected] script]# python suoyin.py
0:fu
1:shan
2:hua
3:hive
另外一种方式：

[[email protected] script]# vim suoyin.py
#!/usr/bin/python
# coding:utf-8

alist = [‘fu‘,‘shan‘,‘hua‘,‘hive‘]

#for i in range(len(alist)):
#    print ‘%s:%s‘ % (i,alist[i])


for i in enumerate(alist):
    print ‘%s:%s‘ %(i[0],i[1])

检验：
[[email protected] script]# python suoyin.py
(0, ‘fu‘)
(1, ‘shan‘)
(2, ‘hua‘)
(3, ‘hive‘)

[[email protected] script]# vim suoyin.py
#!/usr/bin/python
# coding:utf-8

alist = [‘fu‘,‘shan‘,‘hua‘,‘hive‘]

#for i in range(len(alist)):
#　　print ‘%s:%s‘ % (i,alist[i])

for i in enumerate(alist):
　　print ‘%s:%s‘ % (i[0],i[1])

检验：

[[email protected] script]# python suoyin.py
0:fu
1:shan
2:hua
3:hive

还可以：

[[email protected] script]# vim suoyin.py   
#!/usr/bin/python
# coding:utf-8

alist = [‘fu‘,‘shan‘,‘hua‘,‘hive‘]

for m,n in enumerate(alist):
    print ‘%s:%s‘ % (m,n)

检验：
[[email protected] script]# python suoyin.py
0:fu
1:shan
2:hua
3:hive

#######列表一些简单用法############

In [10]: alist = [23,10,45,33]

In [11]: reversed(alist)
Out[11]: <listreverseiterator at 0x7f44bd7c3910>

In [12]: list(reversed(alist))
Out[12]: [33, 45, 10, 23]

In [15]: sorted(alist)           #从小到大，升序
Out[15]: [10, 23, 33, 45]

  In [16]: list(reversed(sorted(alist)))      #降序排列
  Out[16]: [45, 33, 23, 10]

  或者：

  In [18]: sorted(alist)[::-1]

  Out[18]: [45, 33, 23, 10]

##########字符串格式化############

In [19]: ‘%10s%s‘ % (‘name‘,‘fush‘)     ##‘%10s‘ 右对齐，占是个字符，不够的用空格补上；默认右对齐
Out[19]: ‘      namefush‘

In [20]: ‘%10s %s‘ % (‘name‘,‘fush‘)
Out[20]: ‘      name fush‘

In [21]: ‘%-10s %s‘ % (‘name‘,‘fush‘)         ##‘%-10s‘ 左对齐，占是个字符，不够的用空格补上

  Out[21]: ‘name      fush‘

还有一种不常用的用法：

1 In [22]: ‘%*s %*s‘ % (-20,‘name‘,-8,‘fush‘)    ##在s前面用*号，在后面用数字代替
2 Out[22]: ‘name                 fush    ‘

格式化案例：

 1 [[email protected] script]# vim  huamian.py   
 2 #!/usr/bin/python
 3 # coding:utf-8
 4 
 5 
 6 def get_content():
 7     contents = []
 8     while True:
 9         data = raw_input(‘<Enter to quit>: ‘)
10         contents.append(data)
11         if not data:
12             break
13     return contents
14 
15 if __name__ == ‘__main__‘:
16     width = 48
17     lines = get_content()
18     lines.pop()
19     print ‘+%s+‘ % (‘#‘ * width)
20     for line in lines:
21         if not len(line)%2:
22             sp_width = (width -len(line)) / 2
23             print ‘+%s%s%s+‘ % (‘ ‘ * sp_width,line,‘ ‘ * sp_width)
24         else:
25             sp_width = (width -len(line)) / 2
26             print ‘+%s%s%s +‘ % (‘ ‘ * sp_width,line,‘ ‘ * sp_width)
27     print ‘+%s+‘ % (‘#‘ * width)

改进版：

 1 #!/usr/bin/python
 2 # coding:utf-8
 3 
 4 
 5 def get_content():
 6     contents = []
 7     while True:
 8         data = raw_input(‘<Enter to quit>: ‘)
 9         if not data:
10             break
11         contents.append(data)
12     return contents
13 
14 if __name__ == ‘__main__‘:
15     width = 48
16     lines = get_content()
17     print ‘+%s+‘ % (‘#‘ * width)
18     for line in lines:
19         sp_width , extra = divmod((width -len(line)),2)
20         print ‘+%s%s%s+‘ % (‘ ‘ * sp_width,line,‘ ‘ * (sp_width + extra))
21     print ‘+%s+‘ % (‘#‘ * width)
备注：num1,num2 = divmod(10,2)
num1 = 10/2 的商
num2 = 10/2 的余数
奇数/2 的余数（num2=1）
偶数/2 的余数（num2=0） 

验证效果：

1 [[email protected] script]# python  huamian.py
2 <Enter to quit>: hello
3 <Enter to quit>: world!
4 <Enter to quit>: 
5 +################################################+
6 +                     hello                      +
7 +                     world!                     +
8 +################################################+