Understanding Objective-C Method Invocation and Execution Issues Introduction In this article, we will delve into the world of Objective-C method invocation and execution issues. We will explore why a custom method is not being called in certain situations, even when its implementation appears to be correct. This issue can be particularly frustrating for developers who are familiar with the language but struggle to understand why their code is not behaving as expected.

Understanding the Facebook Graph API v2.4 Birthday Endpoint The Facebook Graph API is a powerful tool for accessing user data, but it has its limitations. In this article, we will delve into the specifics of the birthday endpoint in version 2.4 of the Graph API and explore how to retrieve user birthdays successfully. Introduction to the Facebook Graph API The Facebook Graph API allows developers to access user data, including profile information, friends lists, and more.

Specifying Columns as Axes in Matplotlib and Plotting Bar Charts Introduction Matplotlib is a popular Python library for creating high-quality 2D and 3D plots, charts, and graphs. One of the common use cases for matplotlib is to plot bar charts. However, when you have a DataFrame with multiple columns and want to plot one column as the X-axis and another column as the Y-axis, you might encounter some issues. In this article, we will explore how to specify columns as axes in matplotlib and plot bar charts using Python.

Step 1: Initialize the new column ‘Trend 20 Window’ with empty string df[‘Trend 20 Window’] = ’’ # init to '’ Step 2: Define the rolling window size periods = 20 Step 3: Create a mask for rows where both conditions are met within the rolling window mask = df[‘20MA’].gt(df[‘200MA’]).rolling(periods).sum().ge(1) & df[‘20MA’].lt(df[‘200MA’]).rolling(periods).sum().ge(1) Step 4: Assign ‘Neutral’ to rows in ‘Trend 20 Window’ where the mask is True df.loc[mask, ‘Trend 20 Window’] = ‘Neutral’

Understanding Map Annotations and Performance Optimization As we’ve all experienced, working with maps can be a daunting task, especially when it comes to optimizing performance. One of the most common issues developers face is dealing with a large number of map annotations. In this article, we’ll explore how to reduce the number of annotations on a map without compromising its accuracy. Background: How Map Annotations Work Before diving into the solution, let’s quickly review how map annotations work.

Creating New Folder/Directory in Python/Pandas Introduction In this article, we will explore the process of creating a new folder or directory in Python using the popular pandas library. We’ll delve into the underlying mechanics and provide practical examples to help you master this essential skill. Error Analysis The provided Stack Overflow post highlights an error where creating a new folder throws an IOError. Let’s break down the issue: IOError: [Errno 2] No such file or directory: 'H:/Q4/FOO_IND.

Introduction In this article, we will explore the concept of handling missing values in a Pandas DataFrame using Python. Specifically, we will discuss how to implement a logic where if prev_product_id is NaN (Not a Number), then calculate the sum of payment1 and payment2. However, if prev_product_id is not NaN, we only consider payment2. Understanding Pandas DataFrame A Pandas DataFrame is a two-dimensional table of data with rows and columns. Each column represents a variable, and each row represents an observation or record.

Understanding the Problem with Converting Strings to Dates in Swift 4 on Jailbroken iPhones =========================================================== As a developer, it’s not uncommon to encounter issues when working with devices that have been jailbroken. In this article, we’ll delve into the world of date conversions in Swift 4 and explore why converting strings to dates fails on jailbroken iPhone devices. Background: Working with Dates in iOS In iOS, dates are represented using the Date class, which is a part of the Foundation framework.

Plotting Multiple Rasters with Custom Text Labels In this article, we’ll explore how to plot multiple rasters side by side using par(mfrow=c(1,5)) in R, and add custom text labels between the plots. Introduction When working with multiple plots, it’s often necessary to add text labels to indicate what each plot represents. This can be particularly challenging when dealing with a large number of plots, as manually adding each label would be time-consuming and prone to errors.

Mobile Web App Development: iPhone and Android Templates Introduction With the rise of mobile devices, web applications are no longer limited to desktop browsers. Developing a mobile web app requires a different approach than traditional web development. In this article, we will explore the world of mobile web app templates specifically designed for iPhone and Android platforms. What are Mobile Web App Templates? Mobile web app templates are pre-built designs and layouts that can be used as a starting point for developing a mobile web application.