![]() ![]() Upper() converts the entire string into uppercase letters, and lower() into lowercase letters, respectively. Both of them are directly available as methods of the according string object. To allow case-insensitive comparisons Python offers special string methods such as upper() and lower(). The previous examples focused on exact matches between strings. Running the Python script from above the output is as follows: $ python3 comparing-strings-order.py Print ( "%s is similar to %s" % (place, currentCity)) Print ( "%s comes after %s" % (place, currentCity)) Listing 2 shows how these comparison operators work in practice. As an example for the Latin alphabet, "Bus" comes before "bus". Keep in mind the order is case-sensitive. This order depends on the character table that is in use on your machine while executing the Python code. The order depends on the order of the characters in the alphabet. The comparison itself is done character by character. More Comparison Operatorsįor a comparison regarding a lexicographical order you can use the comparison operators, =. > b = 2Ī rule of thumb to follow is to use = when comparing immutable types (like ints) and is when comparing objects. In the next code snippet b gets the value of 2, and subsequently b and c refer to the same object. > a = 1Īs soon as the value changes Python will reinstantiate the object and assign the variable. The two variables a and b have the same value, and Python refers to the same object in order to minimize memory usage. The next example demonstrates that for three variables with integer values. In contrast, the is operator compares two variables based on the object id and returns True if the two variables refer to the same object. = compares two variables based on their actual value. ![]() At first sight they seem to be the same, but actually they are not. Python has the two comparison operators = and is. Running the Python script from above the output is as follows: $ python3 comparing-strings.py Print ( "comparing %s with %s: %s" % (place, currentCity, place = currentCity)) ListOfPlaces = ĬurrentCity = "Lausanne" for place in listOfPlaces: In a for loop, a string containing the name of the Swiss city "Lausanne" is compared with an entry from a list of other places, and the comparison result is printed on stdout. In contrast, the != operator returns True if there is no match and otherwise returns False. ![]() The = operator returns True if there is an exact match, otherwise False will be returned. They work in exactly the same way as with integer and float values. The = and != OperatorsĪs a basic comparison operator you'll want to use = and !=. A number of examples will help you to understand how to use them. Third, to deal with multi-line strings the difflib module is quite handy. Second, we'll go over both the string and the re modules, which contain methods to handle case-insensitive and inexact matches. First, we will explain them in more detail below. In order to compare strings, Python offers a few different operators to do so. Type "help", "copyright", "credits" or "license" for more information. Python tries to re-use objects in memory that have the same value, which also makes comparing objects very fast in Python: $ python Each object can be identified using the id() method, as you can see below. In Python, strings are sequences of characters, which are effectively stored in memory as an object. ![]()
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