This article will show you how to sort a dictionary by the values it contains in the Python programming language. Code examples are included. What is a Dictionary? A dictionary is one of Pythons built in variable types for storing data. Dictionaries are similar to associative arrays or hash tables in other languages. A dictionary contains a collection of values or objects. Unlike lists and arrays, rather than their values being stored at a specific index (the ordered position in the sequence of stored values), values in a dictionary … Read more

The Python sum() function takes a list of numbers, and sums them up (totals/adds them all together). Here’s how to use it, with examples. Summing/Totalling/Adding Numbers The concept of summing numbers is simple – take the numbers you wish to get the total of, and add them all together. 1 + 2 + 3 = 6 It’s basic arithmetic that you’ll use daily when writing computer software in any language. Summing Numbers in Python The sum() function in Python sums numbers. It’s a built-in function, which can be used anywhere … Read more

This article will show you how to calculate natural logs/logarithms in the Python programming language, with examples. What is a Natural Log/Logarithm (ln)? A number’s natural logarithm is it’s logarithm to the base of e. It’s a bit more advanced than the usual arithmetic you’re probably used to seeing as you learn to program, so here’s a bit of explanation: A logarithm is the reverse of an exponent. The logarithm of a number is the exponent that another number must be raised to to produce the first number. You’re … Read more

The Python math.fsum() function takes a list of floating point numbers, and sums them up (totals/adds them all together). Here’s how to use it, with examples. Summing/Totalling/Adding Numbers The concept of summing numbers is simple – take the numbers you wish to get the total of, and add them all together. 1 + 2 + 3 = 6 It’s basic arithmetic that you’ll use daily when writing computer software in any language. Summing Numbers in Python The sum() function in Python sums numbers. It’s a built-in function, which can be … Read more

This article will show you how to iterate/loop over the keys and values in a Python dictionary, and provide code examples. What is a Python Dictionary? In Python, a dictionary is a data type that contains a collection of objects – but unlike a list or array, rather than their values being recorded at a specific index (or ordered position in the sequence of stored values), they are stored in a key – a string identifier which both tells you what a value is for, and which … Read more

This article will show you how to generate CSV (Comma Separated Values) data, and write it to a file, with examples. What is CSV (Comma Separated Values) CSV (Comma Separated Values) is a format for storing and transmitting data, usually in a text file, in which the individual values are separated by a comma (,). Each row in a CSV file represents an individual record containing multiple comma separated values. A CSV file looks like this: name,age,favourite colour Fred,54,green Mary,31,pink Steve,12,orange Above, the CSV describes three people, with … Read more

The hasattr() function is used to check whether an object has a given named attribute. Here is how it is used, with examples. Python Objects and Classes Python is an object oriented programming language. Object oriented means that rather than code being written as a list of instructions, accumulating data and passing the results to the following lines of code (known as procedural programming), data and functionality is contained within the objects it describes. Each object is a self-contained representation of something, that can be modified, and passed between functions … Read more

This quick tutorial will show you how to reverse a string in Python, and provide example code. Strings in Python Strings in Python are defined using quotes or double quotes, and assigned to variables: string1 = “This is a string” string2 = ‘This is also a string’ Strings are used to store non-numeric values – things like names, words, sentences, and serialized data. There’s a lot you can do with Python strings. Strings are immutable — meaning that once defined, they cannot be changed. However, the variable holding … Read more