%可以理解爲就是一個佔位符。
python中用%代表格式符,表示格式化操作,常用的操作有%s,%d,%r等.
%r用rper()方法處理對象
%s用str()方法處理對象
%d十進制整數表示
#!/usr/local/python/bin/python
# -*-coding=utf8 -*-
x = "weiruoyu"
y = 25.66
print "%s" %x
print "%s" %y
print "=========="
print "%r" %x
print "%r" %y
print "=========="
print "%d" %y
print "%d" %x
輸出結果:
weiruoyu
25.66
==========
'weiruoyu'
25.66
==========
25
Traceback (most recent call last):
File "/tmp/testpy/tmp.py", line 17, in ?
print "%d" %x
TypeError: int argument required
Process finished with exit code 1
%d不能讀取字符串,刪除最後一行就可以了。輸出結果如下:
weiruoyu
25.66
==========
'weiruoyu'
25.66
==========
25
下面案例還是有一些小區別:
>>> import datetime
>>> d = datetime.date.today()
>>> print '%s' % d
2018-11-22
>>> print '%r' % d
datetime.date(2018, 11, 22)