There are many ways to merge two lists, and choosing the right way can improve efficiency. 1. Use number splicing to generate a new list, such as list1 list2; 2. Use = to modify the original list, such as list1 = list2; 3. Use extend() method to operate on the original list, such as list1.extend(list2); 4. Use number to unpack and merge (Python 3.5), such as [list1, *list2], which supports flexible combination of multiple lists or adding elements. Different methods are suitable for different scenarios, and you need to choose based on whether to modify the original list and Python version.
I want to merge the two lists, but there are actually quite a lot of methods, and choosing the right method can save a lot of trouble.
use Direct number splicing
This is the most intuitive way. For example, if you have two lists, list1 = [1, 2] , list2 = [3, 4] , write list1 list2 and you can get [1, 2, 3, 4] . This method is suitable for scenarios with small data volume and simple structure. But it should be noted that it does not change the original list, but generates a new list. If you just want to add the content of a list to another, you can use = , such as list1 = list2 , so that list1 will be modified into the merged result.
Use extend() method
This method is operated directly on the original list. For example, list1.extend(list2) , after execution, the content of list1 becomes the result after merge. and The difference is that it won't create new objects, so this method is more appropriate if you care about memory or don't want to retain the original data. Note: This method does not return a value, so it cannot be written as new_list = list1.extend(list2) , so new_list will be None .
Unpacking and merge with * (Python 3.5)
If you are using Python 3.5 and above, you can also merge it by unpacking the asterisk, like this:
combined = [*list1, *list2]
This writing method is not only clear, but can also be used with other structures, such as merging multiple lists or adding extra elements, making it very flexible to write. For example, if you want to add another [5, 6] between two lists, you can write it as [*list1, 5, 6, *list2] , which is more than nested The number is easier to understand.
Basically these commonly used methods
Each method applies slightly different scenarios, depending on whether you need to create a new list or modify the original list, and whether the Python version supports certain syntax. Choosing the right merge method can make the code more concise and easier to maintain.
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