python 常用技巧

1.格式化输出整数

python print也支持参数格式化，与C言的printf似，
<pre name="code" class="html">strHello = '<span style="font-family: Arial, Helvetica, sans-serif;">the length of (%s) is %d ' </span><span style="font-family: Arial, Helvetica, sans-serif;">%</span><span style="font-family: Arial, Helvetica, sans-serif;">(</span><span style="font-family: Arial, Helvetica, sans-serif;">'Hello World',len(</span><span style="font-family: Arial, Helvetica, sans-serif;">'Hello World'</span><span style="font-family: Arial, Helvetica, sans-serif;">))</span>

#输出果：the length of (Hello World) is 11

2.python print 自动换行

print 会自动在行末加上回车,如果不需回车，只需在print语句的结尾添加一个逗号”,“，就可以改变它的行为。

<pre name="code" class="html"><pre name="code" class="python">如：

for i in range(0,5)

   print i,

#输出： 0,1,2,3,4

3.万能的 %

%r是一个万能的格式符，它会将后面给的参数原样打印出来，带有类型信息

"%r %r %r %r"

print formatter % (1,2,3,4)

print formatter % ('one','two','three','four')

print formatter % (True,False,False,True)

print formatter % (

'I had this thing,',

'That you could type up right.',

'But it didn't sing.'

'So I said goodnight.'

)

输出结果：

$ pytyhon ex8.py

1 2 3 4

'one' 'two' 'three' 'four'

True False False True

'%r %r %r %r %r'  '%r %r %r %r %r'  '%r %r %r %r %r'  '%r %r %r %r %r' 

'I had this thing.' 'That you could type up right.' 'but id didn't sing.' 'So I said Goodnight.'

print 会自动在行末加上回车,如果不需回车，只需在print语句的结尾添加一个逗号”,“，就可以改变它的行为。