Python3中如何用Pandas获取CSV数据集维度、打印行及函数实现

Hey there! Let's walk through how to use Pandas in Python 3 to work with your CSV dataset, including fixing your func1 for loading data, printing the dataset's dimensions, and showing sample rows.

1. Fix and Complete the func1 Dataset Loading Function #

Your original code had a few small issues (like overwriting the input parameter), so here's the corrected version that properly loads a CSV with your specified column names:

import pandas as pd

def func1(file_path):
    # Define your custom column names
    names_of_columns = ["The sepal-length", "The sepal-width", 
                        "The petal-length", "The petal-width", "class"]
    # Load the CSV file with the custom column headers
    df = pd.read_csv(file_path, names=names_of_columns)
    return df

# Example usage: Replace with your actual CSV file path
dataset = func1("your_dataset.csv")

Quick breakdown: #

• Takes a file_path parameter (so you can reuse the function for different CSV files)
• Uses pd.read_csv() to load the data, with the names argument setting your custom column labels
• Returns the loaded DataFrame for further operations

2. Print the Dataset's Dimensions #

Once your DataFrame is loaded, use the shape attribute to get the number of rows and columns:

# Get and print full dimensions
rows, columns = dataset.shape
print(f"Dataset has {rows} rows and {columns} columns")

# Or print the shape tuple directly
print(f"Dataset shape: {dataset.shape}")

The shape attribute returns a tuple where the first value is row count, and the second is column count. If you just need the number of dimensions (e.g., 2 for tabular data), use dataset.ndim.

3. Print Partial Rows of the Dataset #

There are several flexible ways to show sample rows from your DataFrame:

Show the first N rows (default is 5) #

print("First 5 rows:")
print(dataset.head())

# To show first 10 rows instead:
# print(dataset.head(10))

Show the last N rows (default is 5) #

print("\nLast 5 rows:")
print(dataset.tail())

Show random sample rows #

print("\nRandom 3 sample rows:")
print(dataset.sample(n=3))

Show specific rows using slicing #

# Show rows 10 to 19 (inclusive)
print("\nRows 10-19:")
print(dataset[10:20])

内容的提问来源于stack exchange，提问作者jacky chen