如何将指定键值对格式数组按规则填充到pandas DataFrame对应列

原代码问题 #

你原有代码的问题在于直接用df[colum] = value赋值，该操作会覆盖对应列的所有行值，既不会自动新增行，也无法实现遇到a开启新行的分组填充逻辑。

正确实现代码 #

import pandas as pd

# 初始化原始数据
data = ["a:42","b:43","c:22","d:41","a:21","b:14","c:12","e:14","f:7","a:0","d:1","f:3","a:6","b:0","c:9","g:8"]
# 存储所有行的列表
rows = []
# 存储当前正在填充的行
current_row = {}

for item in data:
    key, val = item.split(":")
    # 遇到键为a的元素时，先存储上一行，再初始化新行
    if key == "a":
        if current_row:
            rows.append(current_row)
        current_row = {"a": int(val)}
    else:
        # 非a的键值对直接填充到当前行
        current_row[key] = int(val)
# 遍历结束后把最后一行加入列表
rows.append(current_row)

# 转换为DataFrame，指定列顺序，缺失值自动填充为NaN
df = pd.DataFrame(rows, columns=["a","b","c","d","e","f","g"])

输出验证 #

打印df即可得到你期望的结果，所有空缺位置自动填充NaN，数值为整型，列顺序和要求完全一致。

内容的提问来源于stack exchange，提问作者Armando Jose Serrano Escalona