格式化

• 百分比

s = 'hello %s world' %'wuli'
print(s)
#hello wuli world

s = 'hello %.2s world' %'wuli'
print(s)
#hello wu world

s = 'my name is %s,i am %d years old' %('chen', 18)
print(s)
#my name is chen,i am 18 years old

#打印浮点数
s = 'My salary is %f' % 25333.5555555
print(s)
#My salary is 25333.555555

s = 'My salary is %.2f' % 25333.5555555
print(s)
#My salary is 25333.56

#打印百分比
s = 'percent is %.2f %%' % 99.032
print(s)

#打印键值对
s = 'My name is %(name)s, and I am %(age)s years old' %{'name': 'chen', 'age': '18'}
print(s)
#My name is chen, and I am 18 years old

s = 'My name is %(name)-20s, and I am %(age)s years old' %{'name': 'chen', 'age': '18'}
print(s)
#My name is chen                , and I am 18 years old

s = 'My name is %(name)+20s, and I am %(age)s years old' %{'name': 'chen', 'age': '18'}
print(s)
#My name is                 chen, and I am 18 years old

• format 

s = 'My name is {}, and I am {} years old'   #必须一一对应
print(s.format('chen', '18'))
#My name is chen, and I am 18 years old

s = 'My name is {1}, and I am {0} years old'   #不需要一一对应
print(s.format('18', 'chen','abc'))
#My name is chen, and I am 18 years old

s = 'My name is {name}, and I am {age} years old'
print(s.format(name = 'chen', age = '18'))
#My name is chen, and I am 18 years old

s = 'My name is {name}, and I am {age} years old'
print(s.format(**{'name': 'chen', 'age': '18'}))
#My name is chen, and I am 18 years old

s = 'My name is {0[1]}, and I am {1[1]} years old'
print(s.format([0,1,2], [2,25]))
#My name is 1, and I am 25 years old

s = 'My name is {:s}, and I am {:d} years old'
print(s.format('chen', 18))
#My name is chen, and I am 18 years old

s = 'My name is {:s}, and I am {:d} years old'
print(s.format(*['chen', 18]))
#My name is chen, and I am 18 years old

s = 'My name is {name:s}, and I am {age:s} years old'
print(s.format(name = 'chen', age = '18'))
#My name is chen, and I am 18 years old

s = 'My name is {:b}, and I am {:o} years old, {:d}, {:x}, {:X}, {:%}'  #二进制，八进制，整型，小写十六进制，大写十六进制，百分比
print(s.format(15, 15, 15, 15, 15, 15.222222))
#My name is chen, and I am 18 years old