Python format字符串格式化函数的使用

name = 'sugar'
age = 21
print("His name is %s, and he is %d year old." %(name, age))

price = 23.1999
obj = 'milk'

print("The %s's price is %03f" %(obj, price))  # 前面补三个零
print("The %s's price is %3.0f" %(obj, price))  # 最小总占位长度为3，控制输出0个小数
print("The %s's price is %3.3f" %(obj, price))  # 最小总占位长度为3，控制输出3个小数
print("The %s's price is %5.4f" %(obj, price))  # 最小总占位长度为5，控制输出4个小数

price = 23.1999
obj = 'milk'
print("The {}'s price is {}".format(obj, price))

price = 23.1999
obj = 'milk'
print("The {0}'s price is {1}".format(obj, price))

price = 23.1999
obj = 'milk'
info = [obj, price]
print("The {}'s price is {}".format(*info))  # 对info进行解包

price = 23.1999
obj = 'milk'
print("The {name}'s price is {pri}".format(name=obj, pri=price))

# 更进一步，对字典进行解包
dic = {'name':'milk', 'pri':23.1999}
print("The {name}'s price is {pri}".format(**dic))

price = 23.1999
obj = 'bread'
print("The {}'s price is {:.2f}".format(obj, price))  # 使用默认位置方式，保留两位小数
print("The {0}'s price is {1:.2f}".format(obj, price))  # 使用指定位置方式，保留两位小数
print("The {name}'s price is {price:.2f}".format(name=obj, price=price))  # 使用字典方式，保留两位小数

li = [obj, price]
print("The {}'s price is {:.2f}".format(*li))  # 使用列表解包的方式，保留两位小数

info = {'name':obj, 'price':price}
print("The {name}'s price is {price:.2f}".format(**info))  # 使用字典解包的方式，保留两位小数