How to compare two strings in a list in python
Use set intersection for this: Show
gives:
Note that since we are dealing with sets this may not preserve order:
using -- For your example/comment below, this will preserve order (inspired by comment from @DSM)
For a case where the list aren't the same length, with the result as specified in the comment below:
This tutorial will discuss comparing two lists of strings in python. However, at the end of this article, you'll learn the Simplest way to:
Check if the two lists are similarTo check if the two lists are similar, use the == operator. If both lists are similar, it returns True. Otherwise, it returns False. Example:
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Let's see how to use it with the if statement:
Output: Advertisements
Get the duplicated item of two listsThere are many ways to get duplicated items in two lists, but we'll focus on the simple way in the following example. Let's see an example:
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How the program works:
If the above example is hard to understand, we can use the standard syntax:
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Get the unique items of two listsUnique items mean items that are not duplicated in both lists. We'll use the same method as the duplicated example to get the unique items.
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We've used not in operator to check if list_1's items do not exist in list_2. We can also use the set() function to get unique items. Example:
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As you can see, we got the result as a set. To convert Set to List, follow the example below.
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In this article, we will understand the different ways to compare two lists in Python. We often come across situations wherein we need to compare the values of the data items stored in any structure say list, tuple, string, etc.
Methods to Compare Two Lists in PythonWe can use either of the following methods to perform our comparison:
1. Python reduce() and map() functionsWe can use the Python map() function along with functools.reduce() function to compare the data items of two lists. The It applies the passed function to each item of the iterable and then returns a map object i.e. an iterator as the result. The Initially, it would apply the function on the first and the second element and returns the result. The same process will continue on each of the elements until the list has no elements left. As a combination, the map() function would apply the input function to every element and the reduce() function will make sure that it applies the function in a consecutive manner. Example:
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2. Python collection.counter() methodThe collection.counter() method can be used to compare lists efficiently. The counter() function counts the frequency of the items in a list and stores the data as a dictionary in the format If two lists have the exact same dictionary output, we can infer that the lists are the same. Note: The list order has no effect on the counter() method. Example:
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3. Python sort() method and == operator to compare listsWe can club the Python sort() method with the == operator to compare two lists. Python Note: The order of the list does not affect this method because we’ll be sorting the lists before comparison. Further, the Example:
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4. Python set() method and == operator to compare two listsPython set() method manipulates the data items of an iterable to a sorted sequence set of data items without taking the order of elements into consideration. Further, the Example:
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5. Python Custom List Comprehension to Compare Two ListsWe can use Python List comprehension to compare two lists. Example:
In the above code, we set a pointer element ‘x’ to the list l1 and l3. Further, we check if the element pointed by the pointer element is present in the lists. Output:
ConclusionThus, in this article, we have covered and understood a number of ways to compare multiple lists in Python. How do I compare two strings in a list?Use the == and != operators to compare two strings for equality. Use the is operator to check if two strings are the same instance. Use the < , > , <= , and >= operators to compare strings alphabetically.
How do you compare two elements in a list Python?sort() and == operator. The list. sort() method sorts the two lists and the == operator compares the two lists item by item which means they have equal data items at equal positions. This checks if the list contains equal data item values but it does not take into account the order of elements in the list.
Can I use == to compare strings in Python?Python comparison operators can be used to compare strings in Python. These operators are: equal to ( == ), not equal to ( != ), greater than ( > ), less than ( < ), less than or equal to ( <= ), and greater than or equal to ( >= ).
How do you match a string to a list in Python?Python Find String in List using count() We can also use count() function to get the number of occurrences of a string in the list. If its output is 0, then it means that string is not present in the list. l1 = ['A', 'B', 'C', 'D', 'A', 'A', 'C'] s = 'A' count = l1.
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