How to use python format string
1. Introduction to the formatting character function
Application scenarios: Generally, placeholders are provided when print; two formats are provided in python String formatting method: The first is the ancient method of using the percent sign, and the second is the enhanced format string, format function.
2. The ancient percent sign method
1. Common usage
Common placeholder: %s ------------- String placeholder
%d -------------Number placeholder
%f --------------------- -Floating pointNumber placeholder
For example: enter the user's information and print it out
name= raw_input('input your name: ')
age= raw_input ('input your age: ')
job = raw_input ('input your job: ')
msg=''' #定义变量msg，字符串中提供占位符
Information of user %s:
-------------------------------
Name: %s
Age: %s
#特别注意这里，像age这种通过raw_input方式定义的变量，python默认都为字符串，因此这里不用%d,而是用%s
#如果非要用%d的话，那么可以在定义age的时候用函数转换 age= int(raw_input ('input your age: '))
Job: %s
--------------End--------------
'''%(name,name,age,job) #把3个用户定义的变量依次赋给msg字符串中的各个占位符，实现替换,注意4个要按顺序一一对应
print msg
结果：
Information of user Mr.Mangood:
-------------------------------
Name: Mr.Mangood
Age: 27
Job: Engineer
--------------End--------------2. More advanced usage
Account Bit structure: %[(name)][flags][width].[precision]typecode
where:
(name) key
[flags]key
>>> info = '''联系人%(name)s的年龄是%(age)d'''%{'name':'Mr.Mangood','age':23} # 这里可以用字典{'name':'Mr.Mangood','age':23}来对占位符传值
>>> print info
联系人Mr.Mangood的年龄是23When setting the width, for example, 20 characters are set, but when we pass the value, we only write 4 characters. At this time, the concept of alignment appears. Generally, we will use [width] to say
+ Right-justify[width]
Optional, define the placeholder width>>> info = '''联系人%(name)20s的年龄是%(age)d'''%{'name':'Mr.Mangood','age':23} # 这里的20就是宽度[width]，不写[flags]默认右对齐
>>> print info
联系人 Mr.Mangood的年龄是23
>>> info = '''联系人%(name)+20s的年龄是%(age)d'''%{'name':'Mr.Mangood','age':25} # 这里的+20就是右对齐
>>> print info
联系人 Mr.Mangood的年龄是25
>>> info = '''联系人%(name)-20s的年龄是%(age)d'''%{'name':'Mr.Mangood','age':23} # 这里的-20就是代表左对齐
>>> print info
联系人Mr.Mangood 的年龄是23
The number of digits to retain after the decimal point>>> info = '''学生%(name)s的年龄是%(age)d平均成绩为%(avgscore).2f'''%{'name':'Mr.Mangood','age':25,'avgscore':85.2479} #这里的.2就代表%f这个浮点型占位符保留两位小数
>>> print info
学生Mr.Mangood的年龄是25平均成绩为85.25
Required
c %c will convert the incomingintegerdigit into its unicode corresponding value
o Convert the integer to octal representation
>>> s = '''测试ASCII码转换%c测试八进制转换%o测试16进制转换%x'''%(65,9,15) >>> print s 测试ASCII码转换A测试八进制转换11测试16进制转换f
E Convert integers and floating-point numbers into scientific notation (scientific notation) The E in is a capital E)
>>> test = '''测试科学技术法%e测试科学技术法%E'''%(98888888,98888888)
>>> print test
测试科学技术法9.888889e+07测试科学技术法9.888889E+07
## G Automatically identify whether the size of the number needs to be converted into scientific notation (if it exceeds 6 digits, use scientific notation to express it), scientific notation The G in is uppercase
>>> test = '''测试科学技术法%e测试科学技术法%g'''%(123456,123456) >>> print test 测试科学技术法1.234560e+05测试科学技术法123456
>>> zhenli = '''%s是%d%%纯爷们'''%('Mr.Mangood',100)
>>> print zhenli
Mr.Mangood是100%纯爷们The above is the detailed content of How to use python format string. For more information, please follow other related articles on the PHP Chinese website!
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