python学习-22 字符串格式化

格式化包括：百分号方式和format方式

1.百分号

- %s   （%.4s   表示截取了4个字符）

传单个值：

例如：

print('i am %s sex boy is ljj'%123)

运行结果：

i am 123 sex boy is ljj

Process finished with exit code 0

传多个值：

print('i am %s sex boy is %s'%('','ss'))

运行结果：

i am 13 sex boy is ss

Process finished with exit code 0

- %d （只能传数字）

a= 'i am %s, she is %d'%('xm',123)
print(a)

运行结果：

i am xm, she is 123

Process finished with exit code 0

-打印浮点数

a= 'abc %.2f'%99.45678           # .2表示保留小数点后2位（四舍五入）
print(a)

运行结果：

abc 99.46

Process finished with exit code 0

-打印百分比

a= 'abc %.2f %%'%99.45678
print(a)

运行结果：

abc 99.46 %

Process finished with exit code 0

-键值

a= "i am %(name)s ,and age is %(age)d" % {"name":"ljj","age":18}
print(a)

运行结果：

i am ljj ,and age is 18

Process finished with exit code 0

-其他方法

a= "i am %(name)-60s aabbcc" % {"name":"ljj"}    #左对齐60格（+右对齐）
print(a)

运行结果：

i am ljj                                                          aabbcc

Process finished with exit code 0

2.format方式

-传值

a= "i am {},age {},{}" .format("xm",18,123)
print(a)

运行结果：

i am xm,age 18,123

Process finished with exit code 0

-根据索引取值

a= "i am {1},age {0}" .format("xm",18,123)
print(a)

运行结果：

i am 18,age xm

Process finished with exit code 0

-

a= "i am {name},age {age} " .format(name="xm",age=18)
print(a)

运行结果：

i am xm,age 18 

Process finished with exit code 0