《笨办法学python3》的学习笔记（5-9）节

5.更多的变量和打印

在输入更多的变量并且想要将他打印出来的时候。需要使用一个叫做“格式化字符串”的东西每一次使用双引号将一些文本引用起来，就是创建了一个字符串

ex5.py

my_name="Zed A.Shaw"
my_age=35 # not a lie
my_height=74#inches
my_weight=180#lbs
my_eyes='blue'
my_teeth='White'
my_hair='Brown'

print"Let's talk about %s."%my_name
print"He's %d inches tall."%my_height
print"He's %d pounds heavy."%my_weight
print"Actually that's not too heavy."
print"He's got %s eyes and %s hair."%(my_eyes,my_hair)
print"His teeth are usually %s depending on the office."%my_teeth

#this line is tricky,try to get it exactly right
print"If I add %d,%d,and %d I get %d."%(
my_age,my_height,my_weight,my_age+my_height+my_weight)

变量名要以字母开头，所以不能直接使用数字

%s，%r和%d都是一种格式控制工具：表示将右边的变量依次放到左边相应的位置上。 当有多个时，用，隔开。

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6.字符串和文本

字符串可以包含之前看见过的简单的字符串。只需要将格式化的变量放到字符串中，紧跟着一个百分号就可以。需要注意的是如果想要在字符串中通过格式化字符串放入多个变量，需要将变量放到圆括号（（））,而且变量之间是用逗号,隔开。

程序 ex6.py:

x="There are %d types of people."%10
binary="binary"
do_not="don't"
y="Those who know %s and those who %s."%(binary,do_not)

print x
print y
print"I said:%r."% x
print"I also said:'%s.'"% y

hilarious=False
joke_evaluation="Isn't that joke so funny?!%r"

print joke_evaluation%hilarious

w="This is the left side of..."
e="a string with a right side."

print w+e

%r和%s的不同在于：%r会显示原始的数据（raw data）,%s和其他符号则是用来向用户显示输出的，显示变量了

7.更多打印

注意在这个里面的‘snow’其实是字符串而不是变量的名字，变量的名字是不会带引号的

程序ex7.py：

print"Mary had a little lamb."
print"Its fleece was white as %s."%'snow'
print"And everywhere that Mary went."
print"% and #"*10#what'd that do?

end1="C"
end2="h"
end3="e"
end4="e"
end5="s"
end6="e"
end7="B"
end8="u"
end9="r"
end10="g"
end11="e"
end12="r"

#watch that comma at the end .try removing it to see what happens
print end1+end2+end3+end4+end5+end6
print end7+end8+end9+end10+end11+end12

单引号和双引号的区别其实也不是很明显，就是单引号一般被用来创建简短的字符串.

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8.打印，打印

依然还是定义变量和打印输出。

程序ex8.py：

formatter="%r %r %r %r"

print formatter%(1,2,3,4)
print formatter%("one","two","three","four")
print formatter%(True,False,False,True)
print formatter%(formatter,formatter,formatter,formatter)
print formatter%(
"I had this thing.",
"That you could type up right.",
"But it didn't sing.",
"So I said good night."
)

需要注意的一点是在打印语句中。”one”,”two”,”three”,”four”和True，False,False,True这样的区别。ture和false是关键字，用来表示真和假的概念，如果加上了引号就便成了字符串，就没有逻辑平判定的功能了。

9.打印，打印，打印

照例还是定义变量和利用print语句输出一些东西。

程序ex9.py：

#here's some new stange stuff,remember type it exactly

days="Mon Tue Wed Thu Fri Sat Sun"
months="Jan\nFeb\nMar\nApr\nMay\nJun\nJul\nAug"

print"Here are the days:",days
print"Here are the months:",months

print"""
There 's somthing going on here."
With the treee double-quotes."
We'll be able to type as much as we like."
Even 4 lines if we want,or5,or6.
"""

“”“三引号可以将多行的字符串连起来进行输出

\n的意思是进行换行操作，需要指出的是：\n需要放在print语句之中才能够生效。