Python get all elements greater than
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So Justin wins!! With
So Michael wins!!
So Justin wins again!! Let’s start by noting that the key assumption we will be making throughout this article is that the aim is to get the elements as values, not to count them – but return a
list with the corresponding values. Lists are one of the most common data structures used in Python and are created using square brackets To begin, we can create a list. As we are going to be working on finding elements greater than a certain value we will make a list with numbers only – both integers (whole numbers) and floats (decimal places): list1 = [22, 34, 44, 88, 2, 1, 7.5, 105, 333, 7]
Method 1: List ComprehensionArguably the most straightforward way of filtering our list is with list comprehension. This will involve simple code to iterate over each element and compare against a given value. For example, assuming we only want a list containing elements, or items, with a value greater than 7, our syntax would be: list2 = [item for item in list1 if item > 7] print(list2) # [22, 34, 44, 88, 7.5, 105, 333] In the above example, we have asked Python to iterate over each
item in We can also sort the new list if necessary: list2.sort() print(list2) # [7.5, 22, 34, 44, 88, 105, 333] Method 2: The Filter FunctionAs an alternative to list comprehension, we can use the built-in Filter with lambdaJust as a reminder, a lambda function is defined as a small anonymous function (i.e., it has no name) that can take any number of arguments but can only have one expression. list3 = filter(lambda x: x > 7, list1) In the code, we are using our filter function to extract values ( print(list3) # Probably not what you were expecting! This is because in Python version 3 and above the print(list(list3)) # [22, 34, 44, 88, 7.5, 105, 333] Whilst we have the output we want, a key thing to note is that the filter function does not hold any values in memory. Therefore, if we call the list again it will return empty: print(list(list3)) # [] So, if we need to call the list again – as a sorted list, for example, we need to run our lambda function once more: list3 = filter(lambda x: x > 7, list1) print(list(sorted(list3))) # [7.5, 22, 34, 44, 88, 105, 333] Filter without lambdaAs an alternative to lambda, we can also use If we want to create a list of all items greater than 7, we will need to get our function to filter or remove any items less than 7, as follows: list4 = filter((7).__lt__, list1) print(list4) # In the above code the print(list(list4)) # [22, 34, 44, 88, 7.5, 105, 333] As this method still uses the print(list(list4)) # [] To get the list again, this time sorted, we would need to run the function once more but this time we can just request the values sorted: list4 = filter((7).__lt__, list1) sorted(list4) # [7.5, 22, 34, 44, 88, 105, 333] Method 3: Using NumPyA final option would be to use the NumPy module to achieve our goal, but depending on the nature of our initial list, this might be slight overkill. This process is slightly more complex as we need to import the NumPy module and then convert our list into an array as follows: import numpy as np list1 = [22, 34, 44, 88, 2, 1, 7.5, 105, 333, 7] list1 = np.array(list1) print(list1) # array([ 22. , 34. , 44. , 88. , 2. , 1. , 7.5, 105. , 333. , 7. ]) One thing to note is that the integer values have automatically been converted to
floats when the array is created. Once we have list2 = np.sort(list1[list1 > 7]) print(list2) # array([ 7.5, 22. , 34. , 44. , 88. , 105. , 333. ]) Now that we have the correct, sorted values, the last step is to convert them back to a list using the list3 = list3.tolist() # [7.5, 22.0, 34.0, 44.0, 88.0, 105.0, 333.0] ConclusionIn this article we have looked at the various ways of getting elements in a list above a certain value, and once again Python has shown us there are several ways of achieving this. Personally, I find the list comprehension method the most useful as it is simple and does exactly what is required. However, we have used a basic, small data set in our examples so I can appreciate that if you are using large amounts of data using NumPy may be more appropriate as the module is designed to handle more complex data. Whilst the How do you find greater than value in Python?Well, to write greater than or equal to in Python, you need to use the >= comparison operator. It will return a Boolean value – either True or False. The "greater than or equal to" operator is known as a comparison operator. These operators compare numbers or strings and return a value of either True or False .
How do you check if all elements in a list are greater than 0?Using all() function we can check if all values are greater than any given value in a single line. It returns true if the given condition inside the all() function is true for all values, else it returns false.
How do you find the number greater than a value in a list Python?Method 5 : Using bisect() + sort()
The combination of sort() and bisect() , can actually perform the task of binary search, and hence getting the index and subtracting the size of list can actually help us get elements that are greater than particular element in the list.
How do you compare values in a list Python?Using 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.
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