在追加行时，For循环不工作
在追加行时，For循环不工作
提问于 2021-10-10 14:19:19
我试图循环我的数据帧，并为df.con中的每个元素寻找额外的3行，它只循环了第二个元素US和缺少的UK。
请找到附件中的代码。
import pandas as pd
d = { 'year': [2019,2019,2019,2020,2020,2020],
'age group': ['(0-14)','(14-50)','(50+)','(0-14)','(14-50)','(50+)'],
'con': ['UK','UK','UK','US','US','US'],
'population': [10,20,300,400,1000,2000]}
df = pd.DataFrame(data=d)
df2 = df.copy()
df
year age group con population
0 2019 (0-14) UK 10
1 2019 (14-50) UK 20
2 2019 (50+) UK 300
3 2020 (0-14) US 400
4 2020 (14-50) US 1000
5 2020 (50+) US 2000n_df_2 = df.copy()
con_list = [x for x in df.con]
year_list = [x for x in df.year]
age_list = [x for x in df['age group']]
new_list = ['young vs child','old vs young', 'unemployed vs working']
for country in df.con:
bev_child = n_df_2[(n_df_2['con'].str.contains(country)) & (n_df_2['age group'].str.contains(age_list[0]))]
bev_work = n_df_2[(n_df_2['con'].str.contains(country)) & (n_df_2['age group'].str.contains(age_list[1]))]
bev_old = n_df_2[(n_df_2['con'].str.contains(country)) & (n_df_2['age group'].str.contains(age_list[2]))]
bev_child.loc[:,'population'] = bev_work.loc[:,'population'].max() / bev_child.loc[:,'population'].max()
bev_child.loc[:,'con'] = country +'-'+new_list[0]
bev_child.loc[:,'age group'] = new_list[0]
s = n_df_2.append(bev_child, ignore_index=True)
bev_child.loc[:,'population'] = bev_child.loc[:,'population'].max() + bev_old.loc[:,'population'].max()/ bev_work.loc[:,'population'].max()
bev_child.loc[:,'con'] = country +'-'+ new_list[2]
bev_child.loc[:,'age group'] = new_list[2]
s = s.append(bev_child, ignore_index=True)
bev_child.loc[:,'population'] = bev_old.loc[:,'population'].max() / bev_work.loc[:,'population'].max()
bev_child.loc[:,'con'] = country +'-'+ new_list[1]
bev_child.loc[:,'age group'] = new_list[1]
s = s.append(bev_child, ignore_index=True)
s输出缺少UK行...
year age group con population
0 2019 (0-14) UK 10.0
1 2019 (14-50) UK 20.0
2 2019 (50+) UK 300.0
3 2020 (0-14) US 400.0
4 2020 (14-50) US 1000.0
5 2020 (50+) US 2000.0
6 2020 young vs child US-young vs child 2.5
7 2020 unemployed vs working US-unemployed vs working 4.5
8 2020 old vs young US-old vs young 2.0回答 1
Stack Overflow用户
回答已采纳
发布于 2021-10-10 15:15:06
每次通过循环时，s都会重新初始化为以下行上的新数据帧：
s = n_df_2.append(bev_child, ignore_index=True)这使得s最终成为n_df_2的原始值，加上最后一次执行循环体时附加到它后面的三个值。
我认为这更接近于你想要的(在循环改变之前什么都不做)：
for country in df.con.unique():
bev_child = n_df_2[(n_df_2['con'].str.contains(country)) & (n_df_2['age group'].str.contains(age_list[0]))]
bev_work = n_df_2[(n_df_2['con'].str.contains(country)) & (n_df_2['age group'].str.contains(age_list[1]))]
bev_old = n_df_2[(n_df_2['con'].str.contains(country)) & (n_df_2['age group'].str.contains(age_list[2]))]
bev_child.loc[:, 'population'] = bev_work.loc[:, 'population'].max() / bev_child.loc[:, 'population'].max()
bev_child.loc[:, 'con'] = country + '-' + new_list[0]
bev_child.loc[:, 'age group'] = new_list[0]
n_df_2 = n_df_2.append(bev_child, ignore_index=True)
bev_child.loc[:, 'population'] = bev_child.loc[:, 'population'].max() + bev_old.loc[:,
'population'].max() / bev_work.loc[:,
'population'].max()
bev_child.loc[:, 'con'] = country + '-' + new_list[2]
bev_child.loc[:, 'age group'] = new_list[2]
n_df_2 = n_df_2.append(bev_child, ignore_index=True)
bev_child.loc[:, 'population'] = bev_old.loc[:, 'population'].max() / bev_work.loc[:, 'population'].max()
bev_child.loc[:, 'con'] = country + '-' + new_list[1]
bev_child.loc[:, 'age group'] = new_list[1]
n_df_2 = n_df_2.append(bev_child, ignore_index=True)
print(n_df_2)输出：
year age group con population
0 2019 (0-14) UK 10.0
1 2019 (14-50) UK 20.0
2 2019 (50+) UK 300.0
3 2020 (0-14) US 400.0
4 2020 (14-50) US 1000.0
5 2020 (50+) US 2000.0
6 2019 young vs child UK-young vs child 2.0
7 2019 unemployed vs working UK-unemployed vs working 17.0
8 2019 old vs young UK-old vs young 15.0
9 2020 young vs child US-young vs child 2.5
10 2020 unemployed vs working US-unemployed vs working 4.5
11 2020 old vs young US-old vs young 2.0请注意，这只遍历df.con中的唯一值，因此循环体只运行两次。每次循环运行时，都会向输出中添加三条记录。另请注意，输出被附加到n_df_2，因此不需要变量s。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/69515980
复制相关文章
相似问题
腾讯云开发者
