python 3.x 常用字符串格式化

字符串格式化

  • 注意: 加号拼接字符串尽量不要使用,会不断的开辟内存的空间

 1 # 常用字符串格式化
 2 # 1. %s --> 字符串
 3 # 2. %d --> 数字
 4 str_a = "I am %s,age %d" % ("Jayden", 18)
 5 print(str_a) --> I am Jayden,age 18
 6 
 7 # 3. %f --> 浮点(默认小数点后6位且四舍五入)
 8 str_b = "I have money is %f" % 19.123456789
 9 print(str_b) --> I have money is 19.123457
10 
11 # 4. %.2f --> 保留小数点后2位且四舍五入
12 # 5. 百分号的打印形式 --> %%
13 str_c = "percent %.2f%%" % 98.999999999
14 print(str_c) --> percent 99.00%
15 
16 # 6. 用键值对的形式拼接字符串
17 str_d = "I am %(name)s , age %(age)d" % {"name": "June", "age": 18}
18 print(str_d) --> "I am June , age 18"

 

字符串格式化的公式

1 # %[(name)][flags][with].[precision]typecode
2 # (name)        可选      用于选择指定的key
3 # flags         可选      左对齐(+),右对齐(-)
4 # with          可选      占有的宽度
5 # precision     可选      小数点后保留的位数
6 # typecode      必填      s(字符串),d(数字),f(浮点数),e or E(科学计数法)
7 # format常用的字符串格式化

format常用的字符串格式化

 1 str_a = "I am {}, age {}, {}".format("jayden", 30, 'june')
 2 
 3 str_b = "I am {}, age {}, {}".format(*["jayden", 30, 'june'])
 4 
 5 str_c = "I am {0}, age {1}, really {0}".format("jayden", 30)
 6 
 7 str_d = "I am {0}, age {1}, really {0}".format(*["jayden", 30])
 8 
 9 str_e = "I am {name}, age {age}, really {name}".format(name="jayden", age=30)
10 
11 str_f = "I am {name}, age {age}, really {name}".format(**{"name": "jayden", "age": 30})
12 
13 str_g = "I am {0[0]}, age {0[1]}, really {0[2]}".format([1, 2, 3], [11, 22, 33])
14 
15 str_h = "I am {:s}, age {:d}, money {:f}".format("jayden", 30, 88888.1)
16 
17 str_i = "I am {:s}, age {:d}".format(*["jayden", 30])
18 
19 str_j = "I am {name:s}, age {age:d}".format(name="jayden", age=30)
20 
21 str_k = "I am {name:s}, age {age:d}".format(**{"name": "jayden", "age": 30})
22 
23 str_l = "numbers: {:b},{:o},{:d},{:x},{:X}, {:%}".format(15, 15, 15, 15, 15, 15.87623, 2)
24 
25 str_m = "numbers: {:b},{:o},{:d},{:x},{:X}, {:%}".format(15, 15, 15, 15, 15, 15.87623, 2)
26 
27 str_n = "numbers: {0:b},{0:o},{0:d},{0:x},{0:X}, {0:%}".format(15)
28 
29 str_o = "numbers: {num:b},{num:o},{num:d},{num:x},{num:X}, {num:%}".format(num=15)

 

posted on 2018-06-11 13:48  jaydenjune  阅读(78)  评论(0)    收藏  举报

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