详解如何在Pandas中删除常量列

import pandas as pd

# Sample DataFrame with constant and non-constant columns
data = {
    'A': [1, 1, 1, 1],
    'B': [2, 3, 4, 5],
    'C': ['X', 'X', 'X', 'X'],
    'D': [10, 11, 12, 13]
}

df = pd.DataFrame(data)

# Identify constant columns
constant_columns = [col for col in df.columns if df[col].nunique() == 1]

# Display constant columns
print("Constant columns:", constant_columns)

Constant columns: ['A', 'C']

# Drop constant columns
df_cleaned = df.drop(columns=constant_columns)

# Display the cleaned DataFrame
print(df_cleaned)

   B   D
0  2  10
1  3  11
2  4  12
3  5  13

import numpy as np

# Create a DataFrame with random and constant columns
data = {
    'X1': np.random.randint(0, 100, size=100),
    'X2': [5] * 100,    # Constant column
    'X3': np.random.randint(0, 100, size=100),
    'X4': [3] * 100,    # Constant column
}

df_large = pd.DataFrame(data)

# Remove constant columns in the larger dataset
constant_columns = [col for col in df_large.columns if df_large[col].nunique() == 1]
df_large_cleaned = df_large.drop(columns=constant_columns)

print("Original DataFrame Shape:", df_large.shape)
print(df_large.head())

print("Cleaned DataFrame Shape:", df_large_cleaned.shape)
print(df_large_cleaned.head())