Here's an example how you can manage environment variables. To assign a value to a key, utilize os.Setenv. Retrieve a value by key using os.Getenv, which will yield an empty string if the key isn't found. Use os.Environ to list all key/value pairs, returned as a string slice formatted as KEY=value. You can split these strings using strings.SplitN to separate keys and values.
You can write JSON to a file using the json.dump() function from the JSON module combined with file handling in Python. In thisexample, we open a file in writing mode. If the file doesn't exist, it will be created. The json.dump() function converts the Python dictionary into a JSON string, which is then saved in the file.
This exampleillustrates how to read from both a string and a JSON file. Initially, we have a JSON string stored in the variable 'jsonString'. We convert this JSON string into a Python dictionary using json.loads() method, which is then stored in the variable 'jsonDict'. Next, we read a JSON string stored in a file using json.loads(). To achieve this, we first convert the JSON file into a string using file handling, similar to the previous example. Then, we convert it into a string using the read() function. The subsequent steps mirror those followed earlier, utilizing the json.loads() method.
When creating context managers using classes, be sure to ensure that the class includes methods: __enter__() and __exit__(). The __enter__() method provides a resource to be managed, and __exit__() performs cleanup operations without returning any value. To understand the basic structure of building context managers using classes, let's look at a simple FileManager class for managing files.
Channels can be used to synchronize execution between goroutines. Here is an example of using a channel to wait for a goroutine to complete.