Pandas按条件提取行：提取首个F标签出现前所有标签为T的行

实现方法 #

核心思路是先定位TRUE/FALSE列第一个值为F的行的位置，直接截取从开头到该位置之前的所有行即可。

完整示例代码

import pandas as pd

# 构造示例DataFrame
data = {
    "value": [1,2,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4],
    "TRUE/FALSE": ["T","T","T","T","T","T","T","F","F","F","F","F","F","F","T","T","T","T","F","T","F"]
}
df = pd.DataFrame(data)

# 筛选出TRUE/FALSE列为F的布尔序列
f_mask = df["TRUE/FALSE"] == "F"

# 判断是否存在F，避免无F场景报错
if f_mask.any():
    # 取第一个F对应的索引
    first_f_index = f_mask.idxmax()
    # 切片取该索引之前的所有行
    result = df.iloc[:first_f_index]
else:
    # 无F时可根据实际需求调整返回值，此处默认返回全量数据
    result = df

print(result)

输出结果

运行上述代码即可得到预期输出：

value TRUE/FALSE
0      1          T
1      2          T
2      3          T
3      4          T
4      4          T
5      4          T
6      4          T

内容的提问来源于stack exchange，提问作者Jayashree Sridhar