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  • (十四)Python3 字符串格式化

    Python3 字符串格式化 

    字符串的格式化方法分为两种,分别为占位符(%)和format方式。占位符方式在Python2.x中用的比较广泛,随着Python3.x的使用越来越广,format方式使用的更加广泛。

    一 占位符(%)

    %% 百分号标记

    %c 字符及其ASCII码

    %s 字符串

    %d 有符号整数(十进制)

    %u 无符号整数(十进制)

    %o 无符号整数(八进制)

    %x 无符号整数(十六进制)

    %X 无符号整数(十六进制大写字符)

    %e 浮点数字(科学计数法)

    %E 浮点数字(科学计数法,用E代替e)

    %f 浮点数字(用小数点符号)

    %g 浮点数字(根据值的大小采用%e或%f)

    %G 浮点数字(类似于%g)

    %p 指针(用十六进制打印值的内存地址)

    %n 存储输出字符的数量放进参数列表的下一个变量中

    %d

    实例(Python3.0+):

    age = 29
    print("my age is %d" %age)
    #my age is 29
    

    %s

    实例(Python3.0+):

    name = "makes"
    print("my name is %s" %name)
    #my name is makes
    

    %f

    实例(Python3.0+):

    print("%6.3f" % 2.3)
    #2.300
    print("%f" %2.3)
    #2.300000
    

    %% 

    实例(Python3.0+):

    tp1="percent %.2f %%" % 89.1234566
    print (tp1)
    
    #percent 89.12 %
    

    %()type

    实例(Python3.0+):

    info="I am %(name)s , %(age)d years old ." %{"name":"Lucy","age":8}
    print(info)
    
    #I am Lucy , 8 years old
    

    字符串格式控制%[(name)][flag][width][.][precision]type

    name:可为空,数字(占位),命名(传递参数名,不能以数字开头)以字典格式映射格式化,其为键名

    flag:标记格式限定符号,包含+-#0,+表示右对齐(会显示正负号),-左对齐,前面默认为填充空格(即默认右对齐),0表示填充0,#表示八进制时前面补充0,16进制数填充0x,二进制填充0b

    width:宽度(最短长度,包含小数点,小于width时会填充)

    precision:小数点后的位数,与C相同

    type:输入格式类型,请看上面

    info="I am %(name)-10s , %(age)d years old ." %{"name":"Lucy","age":8}
    print(info)
    
    #I am Lucy       , 8 years old .

    补充:

    user='root'
    uid=0
    gid=0
    print(user,uid,gid,sep=":" )
    
    #root:0:0
    

      

    二 format方法

    位置映射

    实例(Python3.0+):

    print("{}:{}".format('192.168.0.100',8888))
    #192.168.0.100:8888
    

       

    关键字映射

    实例(Python3.0+):

    print("{server}{1}:{0}".format(8888,'192.168.1.100',server='Web Server Info :'))
    #Web Server Info :192.168.1.100:8888  
    

    元素访问

    实例(Python3.0+):

    print("{0[0]}.{0[1]}".format(('baidu','com')))
    #baidu.com 

      

    填充对齐

    1. ^、<、>分别是居中、左对齐、右对齐

    实例1(Python3.0+)

    print("{0}*{1}={2:0>2}".format(3,2,2*3))
    
    #3*2=06
     
    
    
    print("{:*^30}".format('centered'))
    
    #***********centered*********** 
    

     

    实例2(Python3.0+):九九乘法表

    for i in range(1,10):
        a = 1
        while a <= i:
            print("{0}*{1}={2:0>2}".format(a,i,a*i),end="	")
            a +=1
        print()
         
    """
    1*1=01 
    1*2=02  2*2=04 
    1*3=03  2*3=06  3*3=09 
    1*4=04  2*4=08  3*4=12  4*4=16 
    1*5=05  2*5=10  3*5=15  4*5=20  5*5=25 
    1*6=06  2*6=12  3*6=18  4*6=24  5*6=30  6*6=36 
    1*7=07  2*7=14  3*7=21  4*7=28  5*7=35  6*7=42  7*7=49 
    1*8=08  2*8=16  3*8=24  4*8=32  5*8=40  6*8=48  7*8=56  8*8=64 
    1*9=09  2*9=18  3*9=27  4*9=36  5*9=45  6*9=54  7*9=63  8*9=72  9*9=81 
    """
    

    精度设置

    实例(Python3.0+):

    print("{:.3f}".format(2.1415))
    #2.142
    
    print("{:.10f}".format(3.1415))
    #3.1415000000
    

      

     更多使用:

    print("{:,}".format(123456))#输出1234,56
     
    print("{a:w^8}".format(a="8"))#输出www8wwww,填充w
     
    print("%.5f" %5)#输出5.000000
    
    print("%-7s3" %("python"))#输出python 3
     
    print("%.3e" %2016)#输出2.016e+03,也可以写大E
    
    print("%d %s" %(123456,"myblog"))#输出123456 myblog
    
    print("%(what)s is %(year)d" % {"what":"this year","year":2016})#输出this year is 2016
    
    print("{0}{1}".format("hello","fun"))#输出hellofun,这与CSharp的格式化字符(占位符)相似
     
    print("{}{}{}".format("spkk",".","cn"))#输出spkk.cn
    
    print("{a[0]}{a[1]}{a[2]}".format(a=["spkk",".","cn"]))#输出spkk.cn
    
    print("{dict[host]}{dict[dot]}{dict[domain]}".format(dict={"host":"www","domain":"spkk.cn","dot":"."}))#输出www.spkk.cn
    
    print("{a}{b}".format(a="python",b="3"))#输出python3
    
    print("{who} {doing} {0}".format("python",doing="like",who="I"))#输出I like python
    
    print ('number:{1:d}:{2:.2f}:{3:e}:{4:%}'.format(*[1,2,3000,4,5,])) #输出 number:2:3000.00:4.000000e+00:500.000000%
    
    print ('number:{num:o}:{num:0>.2f}:{num:b}:{num:x}:{num:X}'.format(num=15)) #输出 number:17:15.00:1111:f:F
    

      

     1 print("{:,}".format(123456))#输出1234,56
     2 
     3 print("{a:w^8}".format(a="8"))#输出www8wwww,填充w
     4 
     5 print("%.5f" %5)#输出5.000000
     6 
     7 print("%-7s3" %("python"))#输出python 3
     8 
     9 print("%.3e" %2016)#输出2.016e+03,也可以写大E
    10 
    11 print("%d %s" %(123456,"myblog"))#输出123456 myblog
    12 
    13 print("%(what)s is %(year)d" % {"what":"this year","year":2016})#输出this year is 2016
    14 
    15 print("{0}{1}".format("hello","fun"))#输出hellofun,这与CSharp的格式化字符(占位符)相似
    16 
    17 print("{}{}{}".format("spkk",".","cn"))#输出spkk.cn
    18 
    19 print("{a[0]}{a[1]}{a[2]}".format(a=["spkk",".","cn"]))#输出spkk.cn
    20 
    21 print("{dict[host]}{dict[dot]}{dict[domain]}".format(dict={"host":"www","domain":"spkk.cn","dot":"."}))#输出www.spkk.cn
    22 
    23 print("{a}{b}".format(a="python",b="3"))#输出python3
    24 
    25 print("{who} {doing} {0}".format("python",doing="like",who="I"))#输出I like python

      

     

     

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  • 原文地址:https://www.cnblogs.com/a-ant/p/10987220.html
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