python delete item from list

)Define Dictionary using a pair of large (curly) brackets "{}".A dictionary (Dictionary) is one of the built-in data types of Python that defines a one-to-one relationship between keys and values, but they are stored in a disorderly manner. The "value" in the dictionary is referenced by a key. Unlike lists: dictionaries are unordered, and the dictionaries are accessed by keys to access members.Dictionaries are mutable and can contain any other type St

to reverse the list.Xx.sort ()Xx.reverse ()Meta-groupA python tuple is similar to a list, except that the elements of a tuple cannot be modified . tuples use parentheses, and the list uses square brackets. Dictionary key key valueNote that in the dictionary operation, the dictionary is judged by the keymodifying elementsThe data in each element of the dictionary

You can think of a list in Python as a sequence of arbitrary pairs of images, as long as you put the required parameter values into brackets [], just like this:names = [' Ada ', ' Amy ', ' Ella ', ' Sandy ']The list can contain different types of images, and nesting is also supported:For example a = [' A ', 567,[' ADC ', 4,], (on)]This

(inpot)SCR = 17+text #设置一个长度left = (SCR)//2 #设置前方空格的空隙#下方输出的内容可以根据输入字符串的长度进行变化Print #输出空print ' * left + ' + ' + '-' * (SCR) + ' + 'print ' * left + ' | ' + ' *SCR + ' | 'print ' * left + ' | ' + ' Nice to meet you: ' +inpot+ ' | 'print ' * left + ' | ' + ' *SCR + ' | 'print ' * left + ' + ' + '-' * (SCR) + ' + ' Little Exercise 2 Second, the initial knowledge of the tuple 1, the following is a normal tuple >>> name = (' A ', ' B ', ' C ')>>> Name(' A ', ' B ', ' C ') Th

[Python] python3 file operations: input files from the keyboard, open and close files, read and write files, rename and delete files, etc,1. Input from the keyboard Python 2 has two built-in functions used to read data from standard input, which are by default from the keyboard. These two functions are: input () and raw_input ().In

official site is the direction of python. you can think of it as python. >>> La [1, 2, 3, 'A', 'B', 'C', 'qiwsir ', 'Python'] >>> la. index (3) 2> la. index ('A') 3 >>> la. index (1) 0 >>> la. index ('qi ') # if it does not exist, the error Traceback (most recent call last) is returned: File" ", Line 1, in ValueError: 'QI' is not in

Recently, I became interested in Python. So I downloaded some basic Python books and documents from the Internet and started learning python. I found that the list object function in python is very powerful, programming is much easier than other programming languages to perf

) # NOTE: There is no 5 in la, but if this method is used, no error is returned, and the number 00 is returned. Position of an element in the list As mentioned in "a large list (1)", the elements in the list can be numbered from left to right from 0 to create an index (if the index is from right to left, numbers starting from-1). An index can be used to extract a

method: removeSet ([' Y ', ' python ', ' B ', ' O '])>>> a.remove (' python ')>>> ASet ([' Y ', ' b ', ' O ']) Traversal of the 3.SET collection Traverse set: Def iterset (): s = set ([]) for item in s: print (item) for I in enumerate (s): print (i) 4.

Create ListOne of the data types built into Python is the list: list . A list is an ordered set of elements that can be added and removed at any time.For example, by listing the names of all the classmates in the class, you can use a list to indicate:>>> [' Michael ', ' Bob

Dive into Python says that a tuple is an immutable list, and once a tuple is created, it cannot be changed in any way. But a Tuple operates faster than a list. If you define a constant set of values and the only thing you want to do with it is to iterate over it, use tuple instead of list. I wrote a few lines of code t

Python does not need to declare type information because the Python variable identifier does not have a type.When a list is created in Python, the interpreter creates an array-like data structure class in memory to store the information, and the data items are stacked up from bottom up (forming a stack). The index star

Creation of lists1, common method to create a listlist = []2, list analysis, List deduction typeUsing list parsing can be almost 1 time times faster than using a normal method. It is therefore recommended to use list parsing.Grammar[Expression for Iter_val in iterable if COND_EXPR]Requirements:

an empty part. C. Similarly, assigning an empty part to a part can be used to delete the part. 3. List Method1) appendLst. append (XXX): note that no return value is returned!2) countCount the number of times an element appears in the list: lst. Count (XXX) 3) ExtendAppend multiple values to the end of a sequenceA. Extend (B) appends B to the end of a, and a cha

location and returns the index position. If you return 0, you will find it in the 0 position instead of the one you found. If you don't find it, you throw the exception directly.>>> username = ' Hello,world '>>> username.index (' l ') #返回位置2>>> username.index (' h ') #返回0的位置0>>> username.index (' x ') #找不到, throw an exceptionTraceback (most recent call last):File "Valueerror:substring not foundInsert inserts data----exact locationInserts data into the list