python核心编程(第二版)--学习笔记--2.1

python交互解释器

linux shell

print输出变量的值。---------------------------------------------------------Python 3.4.3 (default, Nov 28 2017, 16:41:13) [GCC 4.8.4] on linuxType 'help', 'copyright', 'credits' or 'license' for more information.>>> mystring = 'Hello World!'>>> print (mystring)Hello World!>>>

交互解释器输出变量的值-------------------------------------------------------------->>> mystring'Hello World!'

print的输出是调用了str()---------------------------------------------------------------->>> str(mystring)'Hello World!'

交互解释器输出是调用了repr()------------------------------------------------------------------>>> repr(mystring)''Hello World!''

交互解释器中”_' 有特别含意，表示最后一个表达式的值----------------------------------------------------------------------------->>> _''Hello World!''

print格式化输出---------------------------------------------------------------------->>> print ('%s is number %d!' % ('python',1))python is number 1!

print >>重定向输出-------------------------------------------------------------------------->>> print ('Fatal error:invalid input!',file=sys.stderr)Fatal error:invalid input!