下面的代码在for循环中生成给定范围内的随机整数,我想将这些值分配给numpy数组Values, up_value_one,up_value_two
,但下面的for循环不起作用。Values, up_value_one,up_value_two
的值作为空数组返回。如何使用appender
作为变量将a,b,c
附加到Values, up_value_one,up_value_two
并更新数组?
import numpy as np
from random import seed
from random import randint
# seed random number generator
seed(1)
def MXincrementedUpside():
Values = np.array([])
up_value_one= np.array([])
up_value_two= np.array([])
for x in range(3):
a = randint(0, 20)
b = randint(0, 10)
c = randint(0, 15)
for appender,vals in zip([Values, up_value_one,up_value_two],
[a,b,c]):
appender = np.append(appender,vals)
return {'Percentage Change': Values, 'Initial %':up_value_one,'Ending %':up_value_two}
result = MXincrementedUpside()
print(result)
预期输出:
{'Percentage Change': array([1, 3,17], dtype=float64), 'Initial %': array([6,9,10], dtype=float64), 'Ending %': array([11,12,3], dtype=float64)}
在for循环内部的每次迭代中都要声明一个新的appender
,因为np.append
没有附加到位,所以不会保存任何内容。我建议您使用list.append
,然后转换为np.array
。
如果您使用list.append
,那么您的代码只需要最少的更改。只需将Values
、up_value_one
和up_value_two
更改为列表,即可使用list.append
。由于它附加到位,所有这些列表都会在循环中更新:
def MXincrementedUpside():
Values = []
up_value_one = []
up_value_two = []
for x in range(3):
a = randint(0, 20)
b = randint(0, 10)
c = randint(0, 15)
for appender,vals in zip([Values, up_value_one,up_value_two],
[a,b,c]):
appender.append(vals)
return {'Percentage Change': np.array(Values), 'Initial %': np.array(up_value_one),'Ending %': np.array(up_value_two)}
但如果你坚持使用np.append
,下面是一种方法:
def MXincrementedUpside():
Values = np.array([])
up_value_one= np.array([])
up_value_two= np.array([])
for x in range(3):
Values = np.append(Values, randint(0, 20))
up_value_one = np.append(up_value_one, randint(0, 10))
up_value_two = np.append(up_value_two, randint(0, 15))
return {'Percentage Change': Values, 'Initial %':up_value_one, 'Ending %':up_value_two}