Python，如何将此公式应用于数据库中的每一行，以便每一行给出不同的值，而不是每年给出相同的值

这是我的代码。对于2001、2002、2003等，它只返回一个值。我宁愿返回不同的值。轴-1是否可以工作，如果可以，我应该将其放在哪里？

# Define a function to map the values
def set_value(row_number,assigned_value):
return assigned_value[row_number]
#Create the dictionary
year_dictiOnary={'2001' : np.random.randint(1,202335),'2002' : np.random.randint(1,188846),'2003' : np.random.randint(1,175357),"2004" : np.random.randint(1,161868),"2005" : np.random.randint(1,148379),"2006": np.random.randint(1,134890),"2007" : np.random.randint(1,121401),"2008" : np.random.randint(1,107912),"2009" :np.random.randint(1,94423),"2010" :np.random.randint(1,80934),"2011" :np.random.randint(1,67445),"2012" :np.random.randint(1,53956),"2013" :np.random.randint(1,40467),"2014" :np.random.randint(1,26978),"2015" :np.random.randint(1,13489)}
# Add a new column named 'mileage'
df5['mileage'] = df5['year'].apply(set_value,args =(year_dictionary,))


下面是创建df5示例的代码：

df5 = pd.DataFrame(columns=["year","fuel","status","sex","licence_type","mileage"])
# Populate the data with the number of cars per year.
df5['year'] = np.random.choice(["2001","2002","2003","2004","2005","2006","2007","2008","2009",2010,2011,2012,2013,2014,2015],p=[0.004,0.02,0.044,0.087,0.149,0.187,0.221,0.091,0.012,0.031,0.009,0.036,0.013,0.083,0.013],size=(100))
# Populate the Fuel column with petrol and diesel
df5['fuel'] = np.random.choice(['petrol','diesel'],100,p=[0.24,0.76])
# Populate the status column
df5['status'] = np.random.choice(["pass","fail","incomplete"],p=[0.36,0.63,0.01])
# Populate the sex column
df5['sex'] = np.random.choice(['male','female'],p=[0.53,0.47])
# Populate licence_type column
df5['licence_type'] = np.random.choice(["full","learner"],p=[0.92,0.08])
print (df5)


将您的year_dictionary更改为

year_dictiOnary={'2001' : 202335,'2002' : 188846,'2003' : 175357,"2004" : 161868,"2005" : 148379,"2006": 134890,"2007" : 121401,"2008" : 107912,"2009" :94423,"2010" :80934,"2011" :67445,"2012" :53956,"2013" :40467,"2014" :26978,"2015" :13489}


和set_value函数用于

def set_value(row_number,assigned_value):
return np.random.randint(1,assigned_value[row_number])

,

当您声明字典时，它会被声明一次（这意味着随机整数在声明阶段曾经被使用过，之后它们将不会改变）。因此，即使您为特定键（例如：“ 2001”）调用函数，它也会返回与实例化过程中随机生成的值相同的值。

因此，每次需要新随机生成的字典时，都必须更新值。