Get name of array python
I have this code: Show
I restated the problem formulation somewhat. Not sure if etiquette is to post a new question. If so, my bad
where 'string that is representative of my array' equals to 'a', 'b', 'c' or similar. There is likely a better way to solve this, I can just not come up with one right now. What is the best way to do this, fast and efficiently? Note: Python does not have built-in support for Arrays, but Python Lists can be used instead. ArraysNote: This page shows you how to use LISTS as ARRAYS, however, to work with arrays in Python you will have to import a library, like the NumPy library. Arrays are used to store multiple values in one single variable: ExampleCreate an array containing car names: cars = ["Ford", "Volvo", "BMW"] Try it Yourself » What is an Array?An array is a special variable, which can hold more than one value at a time. If you have a list of items (a list of car names, for example), storing the cars in single variables could look like this: car1 = "Ford" However, what if you want to loop through the cars and find a specific one? And what if you had not 3 cars, but 300? The solution is an array! An array can hold many values under a single name, and you can access the values by referring to an index number. Access the Elements of an ArrayYou refer to an array element by referring to the index number. ExampleModify the value of the first array item: cars[0] = "Toyota" Try it Yourself » The Length of an ArrayUse the ExampleReturn the number of elements in the x = len(cars) Try it Yourself » Note: The length of an array is always one more than the highest array index. Looping Array ElementsYou can use the Adding Array ElementsYou can use the ExampleAdd one more element to the
cars.append("Honda") Try it Yourself » Removing Array ElementsYou can use the You can also use the ExampleDelete the element that has the value "Volvo": cars.remove("Volvo") Try it Yourself » Note: The list's Array MethodsPython has a set of built-in methods that you can use on lists/arrays.
Note: Python does not have built-in support for Arrays, but Python Lists can be used instead. Python has a great built-in list type named "list". List literals are written within square brackets [ ]. Lists work similarly to strings -- use the len() function and square brackets [ ] to access data, with the first element at index 0. (See the official python.org list docs.) colors = ['red', 'blue', 'green'] print(colors[0]) ## red print(colors[2]) ## green print(len(colors)) ## 3
Assignment with an = on lists does not make a copy. Instead, assignment makes the two variables point to the one list in memory. b = colors ## Does not copy the list
The "empty list" is just an empty pair of brackets [ ]. The '+' works to append two lists, so [1, 2] + [3, 4] yields [1, 2, 3, 4] (this is just like + with strings). FOR and INPython's *for* and *in* constructs are extremely useful, and the first use of them we'll see is with lists. The *for* construct -- squares = [1, 4, 9, 16] sum = 0 for num in squares: sum += num print(sum) ## 30 If you know what sort of thing is in the list, use a variable name in the loop that captures that information such as "num", or "name", or "url". Since Python code does not have other syntax to remind you of types, your variable names are a key way for you to keep straight what is going on. (This is a little misleading. As you gain more exposure to python, you'll see references to type hints which allow you to add typing information to your function definitions. Python doesn't use these type hints when it runs your programs. They are used by other programs such as IDEs (integrated development environments) and static analysis tools like linters/type checkers to validate if your functions are called with compatible arguments.) The *in* construct on its own is an easy way to test if an element appears in a list (or other collection) -- list = ['larry', 'curly', 'moe'] if 'curly' in list: print('yay') The for/in constructs are very commonly used in Python code and work on data types other than list, so you should just memorize their syntax. You may have habits from other languages where you start manually iterating over a collection, where in Python you should just use for/in. You can also use for/in to work on a string. The string acts like a list of its chars, so RangeThe range(n) function yields the numbers 0, 1, ... n-1, and range(a, b) returns a, a+1, ... b-1 -- up to but not including the last number. The combination of the for-loop and the range() function allow you to build a traditional numeric for loop: ## print the numbers from 0 through 99 for i in range(100): print(i) There is a variant xrange() which avoids the cost of building the whole list for performance sensitive cases (in Python 3, range() will have the good performance behavior and you can forget about xrange()). While LoopPython also has the standard while-loop, and the *break* and *continue* statements work as in C++ and Java, altering the course of the innermost loop. The above for/in loops solves the common case of iterating over every element in a list, but the while loop gives you total control over the index numbers. Here's a while loop which accesses every 3rd element in a list: ## Access every 3rd element in a list i = 0 while i < len(a): print(a[i]) i = i + 3 List MethodsHere are some other common list methods.
Notice that these are *methods* on a list object, while len() is a function that takes the list (or string or whatever) as an argument. list = ['larry', 'curly', 'moe'] list.append('shemp') ## append elem at end list.insert(0, 'xxx') ## insert elem at index 0 list.extend(['yyy', 'zzz']) ## add list of elems at end print(list) ## ['xxx', 'larry', 'curly', 'moe', 'shemp', 'yyy', 'zzz'] print(list.index('curly')) ## 2 list.remove('curly') ## search and remove that element list.pop(1) ## removes and returns 'larry' print(list) ## ['xxx', 'moe', 'shemp', 'yyy', 'zzz'] Common error: note that the above methods do not *return* the modified list, they just modify the original list. list = [1, 2, 3] print(list.append(4)) ## NO, does not work, append() returns None ## Correct pattern: list.append(4) print(list) ## [1, 2, 3, 4] List Build UpOne common pattern is to start a list as the empty list [], then use append() or extend() to add elements to it: list = [] ## Start as the empty list list.append('a') ## Use append() to add elements list.append('b') List SlicesSlices work on lists just as with strings, and can also be used to change sub-parts of the list. list = ['a', 'b', 'c', 'd'] print(list[1:-1]) ## ['b', 'c'] list[0:2] = 'z' ## replace ['a', 'b'] with ['z'] print(list) ## ['z', 'c', 'd'] Exercise: list1.pyTo practice the material in this section, try the problems in list1.py that do not use sorting (in the Basic Exercises). How do you print an array name in Python?To print an array in Python, use the print() function. The print() is a built-in Python function that takes the name of the array containing the values and prints it. To create an array in Python, use the numpy library and create an array using the np. array() function, and then print that array in the console.
How do you check variable names in Python?python-varname is not only able to detect the variable name from an assignment, but also: Retrieve variable names directly, using nameof. Detect next immediate attribute name, using will. Fetch argument names/sources passed to a function using argname.
How do you search an array in Python?Python has a method to search for an element in an array, known as index(). If you would run x. index('p') you would get zero as output (first index).
Is array a list in Python?S.No. List is used to collect items that usually consist of elements of multiple data types. An array is also a vital component that collects several items of the same data type.
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