ChrisHow to Plot a Circle in Python? You can easily plot a circle in Matplotlib’s Pyplot library by calling plt.gca() to “get the current axis”. Then call the axis.add_patch() function and pass a plt.Circle() object into it. For example, the one-liner plt.gca().add_patch(plt.Circle((0.5, 0.5), 0.2, color=’lightblue’)) adds a lightblue circle to the plot at position x=0.5, … Read more
Problem Formulation 💬 How to print a list without quotes in Python? Given a Python list of strings such as [‘1’, ‘2’, ‘3’]. If you print the list to the shell using print([‘1’, ‘2’, ‘3’]), the output is enclosed in square brackets and the strings have quotes like so: “[‘1’, ‘2’, ‘3’]”. This article will … Read more
Problem Formulation Given a Python list of elements. If you print the list to the shell using print([1, 2, 3]), the output is enclosed in square brackets and separated by commas like so: “[1, 2, 3]”. But you want the list without brackets and commas like so: 1 2 3. How to print the list … Read more
Use the tuple concatenation operation * with a tuple with one element (42,) as a right operand and the number of repetitions of this element as a left operand. For example, the expression (42,) * n creates the tuple (42, 42, 42, 42, 42) for n=5. Let’s play with an interactive code shell before you’ll … Read more
Use Python’s built-in min() function with a key argument to find the shortest string in a list. Call min(lst, key=len) to return the shortest string in lst using the built-in len() function to associate the weight of each string—the shortest string will be the minimum. Problem Formulation Given a Python list of strings. Find the … Read more
Use Python’s built-in max() function with a key argument to find the longest string in a list. Call max(lst, key=len) to return the longest string in lst using the built-in len() function to associate the weight of each string—the longest string will be the maximum. Problem Formulation Given a Python list of strings. Find the … Read more
Problem Formulation Given the following DataFrame df: 💬 Challenge: How to apply a function f to each cell in the DataFrame? For example, you may want to apply a function that replaces all odd values with the value ‘odd’. Solution: DataFrame applymap() The Pandas DataFrame df.applymap() method returns a new DataFrame where the function f … Read more
Given an HTML table (code) in a file or at a given URL. First, load all HTML tables into the Python script by calling Pandas’ pd.read_html() passing the URL of the HTML document. The result is a list of DataFrames, one per HTML table in the document. Second, convert any specific DataFrame to a CSV … Read more
The Pandas read_html() function is an easy way to convert an HTML table (e.g., stored at a given URL) to a Pandas DataFrame. You pass a location string or path to it and it returns a list of DataFrames, each representing one table from the location path or URL. The following code, for example, reads … Read more
What is KML? ℹ️ Definition: The Keyhole Markup Language (KML) is a file format for displaying geographic data in Google Earth or other so-called “Earth Browsers”. Similarly to XML, KML uses a tag-based structure with nested elements and attributes. How to Convert KML to CSV in Python? You can convert a .kml to a .csv … Read more
What is GeoJSON? 💡 GeoJSON is an RFC standardized data format to encode geographic data structures such as Point, LineString, Polygon, MultiPoint, MultiLineString, and MultiPolygon. GeoJSON is based on the JavaScript Object Notation (JSON). Example GeoJSON to CSV Say, you have the following GeoJSON snippet: You want to convert it to the following CSV format: … Read more
What is a Fixed-Width File? 💡 Definition: A fixed-width text file contains data that is structured in rows and columns. Each row contains one data entry consisting of multiple values (one value per column). Each column has a fixed width, i.e., the same number of characters, restricting the maximum data size per column. Example of … Read more