import pandas as pd
df = pd.DataFrame({"A": ["a", "b", "c"], "B": ["d", "e", "f"]})
print(df)
print(df["A"])
if "b" in df.A:
print("if b in A")
for i in df.A:
if i == "b":
print("for b in A")
if 1 in df.A:
print("if index in A")
输出
A B
0 a d
1 b e
2 c f
0 a
1 b
2 c
Name: A, dtype: object
for b in A
if index in A
似乎if-in使用数据帧的索引,for-in使用数据帧的值。为什么会有区别,到底有什么区别?
if in
检查"b"
中是否存在df
的条件。for in
将df
中的值分配给变量i
。