常见的python库代码

以下是一些常见的Python库及其代码：

1. NumPy

import numpy as np

# Create a NumPy array
arr = np.array([1, 2, 3, 4, 5])

# Print the array
print(arr)

# Calculate the mean of the array
mean = np.mean(arr)
print(mean)

2. Pandas

import pandas as pd

# Create a Pandas DataFrame
df = pd.DataFrame({'Name': ['Alice', 'Bob', 'Charlie'], 'Age': [25, 30, 35]})

# Print the DataFrame
print(df)

# Get the mean age
mean_age = df['Age'].mean()
print(mean_age)

3. Matplotlib

import matplotlib.pyplot as plt

# Create a simple line plot
x = [1, 2, 3, 4, 5]
y = [2, 4, 6, 8, 10]
plt.plot(x, y)

# Add labels and title
plt.xlabel('X values')
plt.ylabel('Y values')
plt.title('Line Plot')

# Show the plot
plt.show()

4. Scikit-learn

from sklearn.linear_model import LinearRegression

# Create a linear regression model
model = LinearRegression()

# Train the model on some data
X = [[1], [2], [3], [4], [5]]
y = [2, 4, 6, 8, 10]
model.fit(X, y)

# Use the model to make predictions
print(model.predict([[6]]))

5. TensorFlow

import tensorflow as tf

# Create a TensorFlow graph
a = tf.constant(5)
b = tf.constant(10)
c = tf.add(a, b)

# Run the graph
with tf.Session() as sess:
    result = sess.run(c)
    print(result)

6. Flask

from flask import Flask

# Create a Flask app
app = Flask(__name__)

# Define a route and function
@app.route('/')
def hello_world():
    return 'Hello, World!'

# Run the app
if __name__ == '__main__':
    app.run()

7. Django

from django.http import HttpResponse
from django.urls import path
from django.conf.urls import url
from django.views.decorators.csrf import csrf_exempt
from django.views.decorators.http import require_POST

# Define a view function
@csrf_exempt
@require_POST
def hello_world(request):
    return HttpResponse('Hello, World!')

# Define the URL route
urlpatterns = [
    path('hello/', hello_world),
]

# Run the app
if __name__ == '__main__':
    from django.core.management import execute_from_command_line
    execute_from_command_line(['manage.py', 'runserver'])