按列向dataframe添加值

import pandas as pd

# 创建一个初始的DataFrame
data = {
    'A': [1, 2, 3],
    'B': [4, 5, 6]
}
df = pd.DataFrame(data)
print("初始DataFrame:")
print(df)

# 按列添加新的值
new_column_data = [7, 8, 9]
df['C'] = new_column_data
print("\n添加新列后的DataFrame:")
print(df)

初始DataFrame:
   A  B
0  1  4
1  2  5
2  3  6

添加新列后的DataFrame:
   A  B  C
0  1  4  7
1  2  5  8
2  3  6  9

# 示例：列长度不匹配的情况
try:
    df['D'] = [10, 11]  # 长度不匹配
except ValueError as e:
    print(f"错误: {e}")

# 解决方法：确保长度一致
df['D'] = [10, 11, 12]  # 正确的长度
print("\n修正后的DataFrame:")
print(df)

# 示例：数据类型不匹配的情况
try:
    df['E'] = ['a', 'b', 'c']  # 字符串类型
except TypeError as e:
    print(f"错误: {e}")

# 解决方法：转换数据类型
df['E'] = df['E'].astype(str)  # 确保转换为字符串类型
print("\n修正后的DataFrame:")
print(df)