00_python常见用法笔记

分割字符串：

string = "string1"
s = string.split()      #以空格、多空格、\t、\n分割
s = string.split('-')   #使用‘-’分割
#按条件(',', '.', '\n')分割字符串
for i in (',', '.', '\n'):
    s = string.replace(i, ' ')
s = s.split()

 排序sorted()：

#格式：
sorted(list, key, reverse=False)
#key设定：
def bigger_price(data):
    return sorted(data, key=lambda x:x['price'], reverse=True)
print(bigger_price([
    {"name": "bread", "price": 100},
    {"name": "wine", "price": 138},
    {"name": "meat", "price": 15},
    {"name": "water", "price": 1}
]))

out：

[
    {"name": "wine", "price": 138},
    {"name": "bread", "price": 100},
    {"name": "meat", "price": 15},
    {"name": "water", "price": 1}
]

 控制输出位数：

>>> a = 12.1234
>>> b = 12
>>> '%.3f\n' % a
12.123
>>> '%.6f\n' % a
12.123400
>>> '%4d\n' % b
  12
>>> '%04d\n' % b
0012

 注：可以通过round函数实现，通过参数控制保留小数位数

>>> a = 12.1234
>>> b = 3
>>> round(a, b)
12.123