从列表中分配重复值列 [英] Assign column of repeating values from a list

问题描述

假设我有一个数据列表.对于eg [1,2,3,4,5]，我的DataFrame中有1704行.现在，我只想添加具有此值的新列，但应重复到最后一行，如下所示:

Suppose I have a list of data. For eg [1,2,3,4,5] and I have 1704 rows in my DataFrame. Now I want to add new column with this values only but it should be repeated till the last row as shown below:

1  
2  
3  
4  
5  
1  
2  
3  
4  
5  
..  

，依此类推，直到最后一条记录.我尝试了df['New Column']=pd.Series([1,2,3,4,5])，但是它只在前5行中插入记录，但是我希望将此系列重复到最后.我提到了许多关于SO的帖子，但没有找到任何相关的帖子.我是熊猫框架的新手.请帮我解决一下这个.预先感谢.

and so on till the last record. I tried df['New Column']=pd.Series([1,2,3,4,5]) but it inserts record only in first 5 rows but I want this series to be repeated till the last. I referred many posts on SO but didn't found any relevant post. I am a newbie to pandas framework. Please help me with this. Thanks in advance.

推荐答案

下面，我提出两个解决方案，它们也可以处理df的长度不是列表长度的完美倍数的情况.

Below, I propose two solutions that also handle situations where the length of df is not a perfect multiple of the list length.

v = pd.Series([1, 2, 3, 4, 5])
df['NewCol'] = np.tile(v, len(df) // len(v) + 1)[:len(df)]  

---

cycle和islice

具有itertools的纯Python方法.

---

cycle and islice

A pure-python approach featuring itertools.

from itertools import cycle, islice

it = cycle([1, 2, 3, 4, 5])
df['NewCol'] = list(islice(it, len(df)))

这篇关于从列表中分配重复值列的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！