Getting Started with AI in Python: A Simple Machine Learning Example

Artificial Intelligence (AI) is a rapidly evolving field, and Python has emerged as the go-to programming language for AI development. Its simplicity, extensive library support, and strong community make it an excellent choice for beginners and experts alike. In this article, we'll walk through a simple AI example in Python: building a machine learning model to predict house prices.

Why Python for AI?

• Rich Libraries: Libraries like TensorFlow, PyTorch, and scikit-learn simplify AI tasks.
• Ease of Learning: Python’s readable syntax makes it accessible to beginners.
• Community Support: A large community ensures abundant resources and tutorials.

Setting Up Your Environment

Before we start coding, ensure you have Python installed. Then, install the necessary libraries by running:

pip install numpy pandas scikit-learn matplotlib

AI Python Code Example: Predicting House Prices

We will create a machine learning model that predicts house prices based on features like size, number of bedrooms, and age.

Step 1: Import Required Libraries

import numpy as np
import pandas as pd
from sklearn.model_selection import train_test_split
from sklearn.linear_model import LinearRegression
from sklearn.metrics import mean_squared_error
import matplotlib.pyplot as plt

Step 2: Prepare the Dataset

data = {
    "Size (sq ft)": [1500, 2000, 2500, 3000, 3500],
    "Bedrooms": [3, 4, 4, 5, 5],
    "Age (years)": [10, 15, 20, 25, 30],
    "Price (USD)": [300000, 400000, 500000, 600000, 700000]
}
df = pd.DataFrame(data)
print("Dataset:")
print(df)

Step 3: Split the Data

X = df[["Size (sq ft)", "Bedrooms", "Age (years)"]]
y = df["Price (USD)"]
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)
print("Training Features:", X_train)
print("Testing Features:", X_test)

Step 4: Train the AI Model

model = LinearRegression()
model.fit(X_train, y_train)
print("Model Trained Successfully!")

Step 5: Make Predictions

predictions = model.predict(X_test)
print("Predicted Prices:", predictions)
print("Actual Prices:", y_test.values)

Step 6: Evaluate the Model

mse = mean_squared_error(y_test, predictions)
print(f"Mean Squared Error: {mse:.2f}")

Step 7: Visualize the Results

plt.scatter(y_test, predictions)
plt.plot([min(y_test), max(y_test)], [min(y_test), max(y_test)], color='red', linewidth=2)
plt.xlabel("Actual Prices")
plt.ylabel("Predicted Prices")
plt.title("Actual vs Predicted Prices")
plt.show()

Understanding the Output

• Dataset: A table displaying house features and their corresponding prices.
• Predictions: The model predicts house prices based on test data.
• Mean Squared Error: Indicates the error in the model’s predictions.
• Visualization: A scatter plot comparing actual and predicted prices.

Key Takeaways

This example demonstrated how to:

• Prepare a dataset using pandas.
• Split data into training and testing sets.
• Train a linear regression model using scikit-learn.
• Evaluate and visualize the model’s predictions.

Applications of AI in Python

Python-powered AI models are widely used in various domains, including:

• Predictive Modeling: Used in real estate, finance, and marketing.
• Image Recognition: Leveraging TensorFlow for image classification.
• Natural Language Processing (NLP): Using libraries like NLTK and spaCy for text analysis.
• Automation: AI-driven automation for customer support and fraud detection.

Conclusion

This tutorial introduced the fundamentals of AI using Python by building a simple machine learning model to predict house prices. With Python’s rich ecosystem of libraries, AI development is accessible even for beginners.

Now that you’ve learned the basics, you can explore more advanced AI topics, such as deep learning with TensorFlow or PyTorch. Start experimenting today and unlock the power of AI!

Introduction to Artificial Intelligence: A Beginner's Guide

Artificial intelligence (AI) has evolved from a theoretical concept to a transformative technology that impacts nearly every aspect of our daily lives. Whether you're considering a career in AI or simply want to understand this rapidly evolving field, this guide will walk you through the fundamentals of AI and provide a roadmap for your learning journey.

What is Artificial Intelligence?

At its core, artificial intelligence refers to computer systems designed to perform tasks that typically require human intelligence. These include:

• Problem-solving
• Learning from experience
• Understanding natural language
• Recognizing patterns and objects
• Making decisions based on data

The field of AI encompasses several subfields, including machine learning, deep learning, natural language processing, computer vision, and robotics, each with its own specialized focus and applications.

Key Concepts in AI

Machine Learning

Machine learning (ML) is the subset of AI focused on developing systems that improve their performance through experience. Instead of being explicitly programmed for every scenario, ML algorithms learn patterns from data.

The three main types of machine learning are:

1. Supervised Learning: The algorithm learns from labeled training data, making predictions or decisions based on that data.
2. Unsupervised Learning: The algorithm finds patterns in unlabeled data without specific guidance.
3. Reinforcement Learning: The algorithm learns by interacting with an environment, receiving rewards or penalties for actions taken.

Deep Learning

Deep learning is a specialized form of machine learning using neural networks with multiple layers (hence "deep"). These networks mimic the structure and function of the human brain, allowing computers to process complex patterns in large datasets. Deep learning has enabled significant breakthroughs in image recognition, speech processing, and natural language understanding.

Natural Language Processing (NLP)

NLP focuses on enabling computers to understand, interpret, and generate human language. Applications include:

• Virtual assistants (like Siri or Alexa)
• Translation services
• Sentiment analysis
• Text summarization
• Question-answering systems

Computer Vision

Computer vision enables machines to "see" and interpret visual information from the world. This technology powers facial recognition, autonomous vehicles, medical imaging analysis, and quality control in manufacturing.

Getting Started with AI

Prerequisites

Before diving into AI, it's helpful to have:

• Programming Skills: Python is the most widely used language in AI due to its simplicity and extensive libraries.
• Mathematics: A foundation in linear algebra, calculus, probability, and statistics.
• Problem-Solving Skills: The ability to break down complex problems into smaller components.

Learning Path

1. Build Programming Fundamentals
   • Learn Python programming
   • Understand data structures and algorithms
   • Practice with data manipulation libraries like NumPy and Pandas
2. Develop Mathematical Foundations
   • Linear algebra: vectors, matrices, transformations
   • Calculus: derivatives, gradients
   • Statistics and probability: distributions, hypothesis testing
3. Explore Machine Learning
   • Understand basic ML algorithms (linear regression, decision trees, k-means clustering)
   • Learn about model evaluation and validation
   • Practice with scikit-learn library
4. Dive into Deep Learning
   • Study neural network architectures
   • Experiment with frameworks like TensorFlow or PyTorch
   • Build and train your own models
5. Specialize in an Area of Interest
   • Natural Language Processing
   • Computer Vision
   • Reinforcement Learning
   • Robotics

Resources for Learning

Online Courses

• Andrew Ng's Machine Learning courses
• Fast.ai's practical deep learning courses
• Coursera, edX, and Udacity specializations in AI

Books

• "Hands-On Machine Learning with Scikit-Learn, Keras, and TensorFlow" by Aurélien Géron
• "Deep Learning" by Ian Goodfellow, Yoshua Bengio, and Aaron Courville
• "Artificial Intelligence: A Modern Approach" by Stuart Russell and Peter Norvig

Practice Platforms

• Kaggle: Competitions and datasets for hands-on learning
• GitHub: Open-source projects to study and contribute to
• Google Colab: Free cloud-based environment for experimentation

Ethical Considerations in AI

As you learn about AI, it's crucial to understand the ethical implications of these technologies:

• Bias and Fairness: AI systems can perpetuate or amplify existing biases in training data.
• Privacy: Many AI applications involve processing personal data, raising privacy concerns.
• Transparency: The "black box" nature of complex AI models can make decisions difficult to explain.
• Accountability: Determining responsibility for AI-driven decisions remains challenging.
• Job Displacement: Automation through AI may transform employment landscapes.

Next Steps: Hands-On AI with Basic Code Examples

Moving from theory to practice is essential for solidifying your understanding of AI concepts. Here are practical coding examples to get you started with implementing basic AI techniques.

1. Data Preprocessing with NumPy and Pandas

Before building any AI model, you'll need to prepare your data. Here's a simple example of loading and preprocessing data:

import numpy as np
import pandas as pd

# Load dataset
data = pd.read_csv('example_dataset.csv')

# Display basic information
print(data.info())
print(data.describe())

# Handle missing values
data = data.fillna(data.mean())

# Normalize numeric features
from sklearn.preprocessing import MinMaxScaler
scaler = MinMaxScaler()
numeric_features = ['feature1', 'feature2', 'feature3']
data[numeric_features] = scaler.fit_transform(data[numeric_features])

# Convert categorical variables to numerical
data = pd.get_dummies(data, columns=['categorical_feature'])

# Split into features and target
X = data.drop('target', axis=1)
y = data['target']

2. Your First Machine Learning Model: Linear Regression

Linear regression is one of the simplest yet powerful algorithms to start with:

from sklearn.model_selection import train_test_split
from sklearn.linear_model import LinearRegression
from sklearn.metrics import mean_squared_error, r2_score

# Split data into training and testing sets
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)

# Initialize and train the model
model = LinearRegression()
model.fit(X_train, y_train)

# Make predictions
y_pred = model.predict(X_test)

# Evaluate the model
mse = mean_squared_error(y_test, y_pred)
r2 = r2_score(y_test, y_pred)
print(f"Mean Squared Error: {mse}")
print(f"R² Score: {r2}")

# Analyze feature importance
coefficients = pd.DataFrame({'Feature': X.columns, 'Coefficient': model.coef_})
print(coefficients.sort_values(by='Coefficient', ascending=False))

3. Classification with Decision Trees

Decision trees are intuitive models for classification tasks:

from sklearn.tree import DecisionTreeClassifier
from sklearn.metrics import accuracy_score, classification_report
import matplotlib.pyplot as plt
from sklearn import tree

# Assuming a classification dataset
# X_train, X_test, y_train, y_test already prepared

# Create and train the model
clf = DecisionTreeClassifier(max_depth=5, random_state=42)
clf.fit(X_train, y_train)

# Make predictions
y_pred = clf.predict(X_test)

# Evaluate the model
accuracy = accuracy_score(y_test, y_pred)
print(f"Accuracy: {accuracy:.4f}")
print(classification_report(y_test, y_pred))

# Visualize the decision tree
plt.figure(figsize=(15, 10))
tree.plot_tree(clf, feature_names=X.columns, class_names=list(map(str, clf.classes_)), 
               filled=True, rounded=True)
plt.show()

4. Clustering with K-Means

K-means is a popular unsupervised learning algorithm for finding patterns in data:

from sklearn.cluster import KMeans
import matplotlib.pyplot as plt

# Assuming an unlabeled dataset (using only features)
# For simplicity, let's use only two features for visualization
X_subset = X[['feature1', 'feature2']]

# Determine optimal number of clusters
inertia = []
for k in range(1, 11):
    kmeans = KMeans(n_clusters=k, random_state=42)
    kmeans.fit(X_subset)
    inertia.append(kmeans.inertia_)

# Plot elbow curve
plt.figure(figsize=(8, 6))
plt.plot(range(1, 11), inertia, marker='o')
plt.xlabel('Number of clusters')
plt.ylabel('Inertia')
plt.title('Elbow Method for Optimal k')
plt.show()

# Train K-means with optimal k (let's say k=3)
kmeans = KMeans(n_clusters=3, random_state=42)
clusters = kmeans.fit_predict(X_subset)

# Visualize the clusters
plt.figure(figsize=(10, 8))
plt.scatter(X_subset['feature1'], X_subset['feature2'], c=clusters, cmap='viridis')
plt.scatter(kmeans.cluster_centers_[:, 0], kmeans.cluster_centers_[:, 1], 
           marker='X', s=200, c='red', label='Centroids')
plt.title('K-means Clustering Results')
plt.legend()
plt.show()

5. Simple Neural Network with TensorFlow/Keras

This example demonstrates a basic neural network for classification:

import tensorflow as tf
from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import Dense, Dropout
from tensorflow.keras.callbacks import EarlyStopping

# Assuming a classification dataset
# X_train, X_test, y_train, y_test already prepared

# Build the model
model = Sequential([
    Dense(64, activation='relu', input_shape=(X_train.shape[1],)),
    Dropout(0.2),
    Dense(32, activation='relu'),
    Dropout(0.2),
    Dense(1, activation='sigmoid')  # For binary classification
])

# Compile the model
model.compile(optimizer='adam',
              loss='binary_crossentropy',
              metrics=['accuracy'])

# Set up early stopping
early_stopping = EarlyStopping(monitor='val_loss', patience=10, restore_best_weights=True)

# Train the model
history = model.fit(
    X_train, y_train,
    epochs=100,
    batch_size=32,
    validation_split=0.2,
    callbacks=[early_stopping],
    verbose=1
)

# Evaluate the model
loss, accuracy = model.evaluate(X_test, y_test)
print(f"Test Accuracy: {accuracy:.4f}")

# Visualize training history
plt.figure(figsize=(12, 5))
plt.subplot(1, 2, 1)
plt.plot(history.history['accuracy'])
plt.plot(history.history['val_accuracy'])
plt.title('Model Accuracy')
plt.ylabel('Accuracy')
plt.xlabel('Epoch')
plt.legend(['Train', 'Validation'])

plt.subplot(1, 2, 2)
plt.plot(history.history['loss'])
plt.plot(history.history['val_loss'])
plt.title('Model Loss')
plt.ylabel('Loss')
plt.xlabel('Epoch')
plt.legend(['Train', 'Validation'])
plt.tight_layout()
plt.show()

6. Natural Language Processing Example

Here's a simple text classification example using scikit-learn:

from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.naive_bayes import MultinomialNB
from sklearn.pipeline import Pipeline
from sklearn.metrics import accuracy_score, classification_report

# Sample text data and labels
texts = [
    "I love this product, it works great!",
    "This is terrible, complete waste of money",
    "Neutral opinion, neither good nor bad",
    "Amazing service, highly recommend",
    "Disappointed with the quality"
]
labels = [1, 0, 2, 1, 0]  # 1: positive, 0: negative, 2: neutral

# Create training and test sets
X_train, X_test = texts[:3], texts[3:]
y_train, y_test = labels[:3], labels[3:]

# Create a pipeline with TF-IDF and Naive Bayes
text_clf = Pipeline([
    ('tfidf', TfidfVectorizer()),
    ('clf', MultinomialNB())
])

# Train the model
text_clf.fit(X_train, y_train)

# Make predictions
y_pred = text_clf.predict(X_test)

# Print results
print(f"Predictions: {y_pred}")
print(f"Actual: {y_test}")
print(f"Accuracy: {accuracy_score(y_test, y_pred)}")

7. Project Ideas to Practice Your Skills

Now that you have some basic code examples, here are project ideas to apply your knowledge:

1. Predictive Analysis: Build a model to predict house prices based on features like size, location, and amenities.
2. Sentiment Analysis: Create a system that classifies product reviews as positive, negative, or neutral.
3. Image Classification: Develop a model that can identify different types of objects in photographs.
4. Recommendation System: Build a simple recommendation engine for movies or products.
5. Time Series Forecasting: Predict future values of stocks, weather, or energy consumption.

8. Setting Up Your Development Environment

To start working with these examples, set up a Python environment with the necessary libraries:

# Create a virtual environment
python -m venv ai_env

# Activate the environment
# On Windows:
ai_env\Scripts\activate
# On macOS/Linux:
source ai_env/bin/activate

# Install required packages
pip install numpy pandas matplotlib scikit-learn tensorflow

# For GPU support with TensorFlow (optional, requires compatible GPU)
pip install tensorflow-gpu

Looking Forward

Artificial intelligence continues to evolve rapidly. Staying current with the field requires ongoing learning and adaptation. Consider joining AI communities, attending conferences, participating in hackathons, and following research publications to remain at the forefront of developments.

The journey into AI can be challenging but immensely rewarding. With determination and curiosity, you can develop the skills needed to understand, create, and shape the intelligent systems of the future.

Conclusion

Artificial intelligence represents one of the most transformative technologies of our time. By understanding its fundamental concepts and following a structured learning path, you can begin to harness the power of AI for innovation and problem-solving. Remember that learning AI is a marathon, not a sprint—consistent effort and practical application will yield the best results.

As you embark on your AI learning journey, maintain both technical rigor and ethical awareness. The future of AI depends not just on what these systems can do, but on how responsibly they are designed and deployed.

Swift applications follow a structured lifecycle that governs their execution, from launch to termination. Understanding this lifecycle is crucial for managing state, handling user interactions, and optimizing performance.

1. App Launch

When an iOS app launches, it undergoes several stages, including initialization and UI setup. The UIApplicationDelegate handles these transitions.

class AppDelegate: UIResponder, UIApplicationDelegate {
    func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {
        print("App Launched")
        return true
    }
}
    

2. Active and Inactive States

Apps transition between active and inactive states. The active state is when the app is running in the foreground and receiving user input.

func applicationDidBecomeActive(_ application: UIApplication) {
    print("App is active")
}

func applicationWillResignActive(_ application: UIApplication) {
    print("App will become inactive")
}
    

3. Background and Foreground States

When the app moves to the background, it should release resources and save state. Returning to the foreground restores the state.

func applicationDidEnterBackground(_ application: UIApplication) {
    print("App moved to background")
}

func applicationWillEnterForeground(_ application: UIApplication) {
    print("App will enter foreground")
}
    

4. App Termination

When the user or system terminates the app, you can perform cleanup and save essential data.

func applicationWillTerminate(_ application: UIApplication) {
    print("App is terminating")
}
    

5 Ways SwiftUI Will Make You a Better Developer

SwiftUI is more than just Apple’s latest framework for building user interfaces—it’s a game-changer that can elevate your skills as a developer. Whether you’re an iOS veteran or a newcomer to app development, SwiftUI offers tools and approaches that streamline your workflow, enhance your code, and prepare you for the future.

In this article, we’ll explore five ways SwiftUI can transform you into a better developer, complete with practical examples and insights to get you excited about diving in. Ready to level up? Let’s go!

1. Cleaner Code with Declarative Syntax

SwiftUI introduces a declarative programming style that’s like a breath of fresh air compared to the imperative approach of UIKit. Instead of telling the system how to build your UI step-by-step, you simply describe what you want. This shift leads to code that’s more concise, readable, and less prone to bugs.

Example: Button in SwiftUI vs. UIKit

UIKit (Imperative):

let button = UIButton(type: .system)
button.setTitle("Tap Me", for: .normal)
button.addTarget(self, action: #selector(buttonTapped), for: .touchUpInside)
view.addSubview(button)
button.frame = CGRect(x: 100, y: 100, width: 200, height: 50)

SwiftUI (Declarative):

Button("Tap Me") {
    print("Button tapped!")
}
.frame(width: 200, height: 50)

2. Faster Development with Real-Time Previews

One of SwiftUI’s standout features is its real-time preview in Xcode. You can see your UI update instantly as you tweak your code—no need to build and run the app every time.

TextField("Enter text", text: .constant(""))
    .textFieldStyle(RoundedBorderTextFieldStyle())
    .padding()

3. Simpler API for Easier Learning

SwiftUI’s API is designed to be intuitive, flattening the learning curve compared to UIKit’s sprawling ecosystem. With fewer concepts to master, you can pick up SwiftUI quickly and apply it effectively.

NavigationView {
    NavigationLink(destination: Text("Detail View")) {
        Text("Go to Details")
    }
}

4. Built-In Accessibility

SwiftUI encourages inclusive app design from the start, making it easier to support users with diverse needs.

Button("Play Sound") {
    playSound()
}
.accessibilityLabel("Play the notification sound")
.accessibilityHint("Triggers an alert tone")

5. Future-Proofing Your Skills

Apple is all-in on SwiftUI, positioning it as the future of app development. Learning SwiftUI now means staying ahead of the curve.

VStack {
    Text("Hello, World!")
        .font(.title)
    Button("Click Me") {
        print("Clicked!")
    }
}

Conclusion: Unleash Your Potential with SwiftUI

SwiftUI isn’t just a tool—it’s a catalyst for growth. It helps you write cleaner code, develop faster, and stay ahead of the curve. Whether you’re building your next app or sharpening your skills, SwiftUI empowers you to do more with less.

So why wait? Dive into SwiftUI today and see how it transforms your craft. Who knows—your next viral app might just be a few lines of SwiftUI code away!

  I Create custom button apple Sign up apple, error in here code:

private func setupSignUpWithAppleButton() {

        let signUpWithAppleButton: SignInAppleButton = SignInAppleButton()

        signUpWithAppleButton.addTarget(self, action: #selector(didTapSignUpWithAppleButton(_:)), for: .touchUpInside)

        subView.addSubview(signUpWithAppleButton)

        signUpWithAppleButton.fillInSuperview()

    }

This fixing code, with change addTarget to  tap Gesture 

  private func setupSignUpWithAppleButton() {

        let signUpWithAppleButton: SignInAppleButton = SignInAppleButton()

        subView.addSubview(signUpWithAppleButton)

        signUpWithAppleButton.fillInSuperview()

        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(didTapSignUpWithAppleButton))

        signUpWithAppleButton.addGestureRecognizer(tapGesture)

    }

this full custom UIButton

public final class SignInAppleButton: UIButton {

    private lazy var containerView: UIView = {

        let view: UIView = UIView()

        view.translatesAutoresizingMaskIntoConstraints = false

        view.backgroundColor = .clear

        return view

    }()

    private lazy var appleLogoImageView: UIImageView = {

        let imageView: UIImageView = UIImageView()

        imageView.translatesAutoresizingMaskIntoConstraints = false

        imageView.image = UIImage(named: "appleLogo")?.withRenderingMode(.alwaysTemplate)

        imageView.tintColor = .white

        imageView.contentMode = .scaleAspectFit

        return imageView

    }()

    private lazy var textLabel: UILabel = {

        let label: UILabel = UILabel()

        label.translatesAutoresizingMaskIntoConstraints = false

        label.font = .systemFont(ofSize: 16, weight: .medium)

        label.textColor = .white

        return label

    }()

    public init() {

        super.init(frame: .zero)

        setupViews()

    }

    required init?(coder: NSCoder) {

        fatalError("init(coder:) has not been implemented")

    }

    private func setupViews() {

        backgroundColor = .black

        layer.cornerRadius = 6.0

        addSubview(containerView)

        containerView.addSubview(appleLogoImageView)

        containerView.addSubview(textLabel)

        NSLayoutConstraint.activate([

            containerView.topAnchor.constraint(equalTo: topAnchor),

            containerView.bottomAnchor.constraint(equalTo: bottomAnchor),

            containerView.centerXAnchor.constraint(equalTo: centerXAnchor),

            appleLogoImageView.topAnchor.constraint(equalTo: containerView.topAnchor),

            appleLogoImageView.leftAnchor.constraint(equalTo: containerView.leftAnchor),

            appleLogoImageView.bottomAnchor.constraint(equalTo: containerView.bottomAnchor),

            appleLogoImageView.widthAnchor.constraint(equalToConstant: 12),

            textLabel.topAnchor.constraint(equalTo: containerView.topAnchor),

            textLabel.leftAnchor.constraint(equalTo: appleLogoImageView.rightAnchor, constant: 6),

            textLabel.rightAnchor.constraint(equalTo: containerView.rightAnchor),

            textLabel.bottomAnchor.constraint(equalTo: containerView.bottomAnchor)

        ])

        textLabel.text = "Sign up with Apple"

        layoutIfNeeded()

    }

}

 This error when run Unit testing file ex: EditSettingsTests

Unable to load contents of file list: '/Target Support Files/FBAEMKit/FBAEMKit-xcframeworks-input-files.xcfilelist'

Unable to load contents of file list: '/Target Support Files/FBSDKLoginKit/FBSDKLoginKit-xcframeworks-input-files.xcfilelist'

Unable to load contents of file list: '/Target Support Files/FBSDKCoreKit/FBSDKCoreKit-xcframeworks-input-files.xcfilelist'

Unable to load contents of file list: '/Target Support Files/FBSDKCoreKit_Basics/FBSDKCoreKit_Basics-xcframeworks-input-files.xcfilelist'

How to fixing 

1. in 'SettingsTests' set pod like 'Settings' and 'pod install'

example:

# MARK: - Settings

target 'Settings' do

  project 'Features/Settings/Settings'

  pod('FBSDKLoginKit', '12.1.0')

end

# MARK: - SettingsDemo /SettingTests

target 'SettingsDemo' do

  project 'Features/Settings/Settings'

  pod('FBSDKLoginKit', '12.1.0')

  target 'SettingsTests' do

    inherit! :complete

  end

endend

2. in scheme Change 'SettingsTests' and then select edit scheme 

   - tab 'Run' change build configuration from 'Development' to 'Debug(Development)'

   - tab 'Test' change build configuration from 'Development' to 'Debug(Development)'

   - tab 'Profile' change build configuration from 'Production' to 'Adhoc(Production)'

   - tab 'Analyze' change build configuration from 'Production' to 'Adhoc(Production)'

   - tab 'Archive' change build configuration from 'Production' to 'Adhoc(Production)'

   and then 'pod install' again

Note: in Build do not change

3. Run 'SettingsTests' file ex: 'EditSettingsTests'

When work in a project get Errors and how I solve the errors in xcode, Pod, terminal, github, swift code and crash app will be here.


 1. "Pod install" Error

Check this Error screenshot

libc++abi.dylib: terminating with uncaught exception of type NSException
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Mutating a priority from required to not on an installed constraint (or vice-versa) is not supported. You passed priority 500 and the existing priority was 1000.'
terminating with uncaught exception of type NSException
CoreSimulator 776.4 - Device: iPhone 8 (xxxxxx-589A-xxxx-8E6B-xxxxx) - Runtime: iOS 12.4 (16G73) - DeviceType: iPhone 8

try to Debug

Debug
(lldb) po descFirstHeight.priority
▿ UILayoutPriority
- rawValue : 1000.0

(lldb) po descSecondHeight.priority
▿ UILayoutPriority
- rawValue : 500.0

(lldb) po UILayoutPriority.defaultLow
▿ UILayoutPriority
- rawValue : 250.0

(lldb) po UILayoutPriority.defaultHigh
▿ UILayoutPriority
- rawValue : 750.0

(lldb)

Solution
- In XIB dont set (priority = 1000) but you must set (prority = 999)
descFirstHeight =  999
descSecondHeight = 250

- And in file swift 

descFirstHeight.priority = UILayoutPriority.defaultLow // 250

descSecondHeight.priority = UILayoutPriority.defaultHigh // 750

Source: https://stackoverflow.com/a/37474902/8366535

3. In Stackview cannot change color UIView (IOS 12)

Condition when subview in stackview 

example look like this

in phone 8 (IOS 12)

Should be like this
in Iphone 11 (IOS 15)

let see the code Before, it is because in ios 12 the process is slower than ios 15 

//// Code here ///

    private func updateDigitView(_ digitView: UIView, isHighlight: Bool) {

            digitView.backgroundColor = isHighlight ? .cyan : .clear

            

            if let bulletView = digitView.subviews.last {

                bulletView.backgroundColor = isHighlight ? .blue : .clear

                bulletView.layer.borderWidth = isHighlight ? 0 : 1

                bulletView.layer.borderColor = isHighlight ? nil : UIColor.cyan.cgColor

            }

    }

//// ----------- ///

SOLUTION

So this my solution can fix that problem use dispatchqueue async

//// Code here ///

 private func updateDigitView(_ digitView: UIView, isHighlight: Bool) {

     DispatchQueue.main.async {

            digitView.backgroundColor = isHighlight ? .cyan : .clear

            

            if let bulletView = digitView.subviews.last {

                bulletView.backgroundColor = isHighlight ? .blue : .clear

                bulletView.layer.borderWidth = isHighlight ? 0 : 1

                bulletView.layer.borderColor = isHighlight ? nil : UIColor.cyan.cgColor

            }

        }

    }

//// ----------- ///

4. Error build after (pod install)

error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.

How to Solve

- clean build/ delete DrivedData

- pod install / pod update (again)

If still an error

- checkout to branch development/master and build app.
- If in branch master not failed back into your branch and build your app again

5. UserDefaults JSON
this example use pod swiftyJson

// set

if let model = JSON["data"].rawString(.utf8, options: .fragmentsAllowed) {

  UserDefaults.standard.setValue(model, forKey: "UserDefaultKey")

 }

//call

guard let status = UserDefaults.standard.string(forKey: "UserDefaultKey"), let data = statusOA.data(using: .utf8) else {

return nil }

6. Nil when passing data Model

When I passing optional data model like this 
example: 

In Model

struct Form: Codable {

var isValue: Bool?

var isUsed: Bool?

enum CodingKeys: String, CodingKey {

case isValue, isUsed

}

init(from decoder: Decoder) throws {

let container = try decoder.container(keyedBy: CodingKeys.self)

isUsed = try container.decodeIfPresent(Bool.self, forKey: .isUsed)

isValue = try container.decodeIfPresent(Bool.self, forKey: .isValue)

}

}

In View Controller

var form: Form?

//When Passing from API Response

.

.

.

form = response?.form

.

.

.

print(form.isValue) // nil

Solution is  create a new request model with parameter

struct FormModel {

struct Request {

var parameters: [String: String]?

public init(isValue: Bool, isUsed: Bool) {

parameters = [

"isValue": "\(isValue)",

"isUsed": "\(isUsed)"

]

}

}

}

/////------/////------/////------/////------/////------

// in viewDidLoad example

form = FormModel.Request(isValue: true, isUsed: false)

// now is not nil

7. Error Need Install `cocoapods-keys`

Not running with Xcode Cloud, setup podfile with cocoapod-keys plugin

[!] Your Podfile requires that the plugin `cocoapods-keys` be installed. Please install it and try installation again.

The problem is my git change from `https` to `ssh` setting so my old version ruby is `2.6.1` update to `3.1.2`

Solution

- delete old `cocoapod-keys-App ` in Keychain access

$arch 

$ruby -v   

$brew     

$brew install rbenv ruby-build

$rbenv install 3.1.2  

$rbenv global 3.1.2    

$open ~/.zshrc  

$ruby -v 

$gem install cocoapods-keys

$gem install cocoapods

$gem install fastlane

$cd app    

$pod install 

8. When Cannot Run "xed ." in terminal  

This Error

app: $xcode-select --install

xcode-select: error: command line tools are already installed, use "Software Update" to install updates

Solution:

xcode-select --install

sudo xcode-select -s /Applications/Xcode.app/Contents/Developersudo xcodebuild -license accept