Some common Python methods compiled for your reference
This article mainly introduces some common methods and techniques in the collection of Python. This article explains three methods of reversing strings, four methods of traversing a dictionary, and traversing a list Three methods, dictionary sorting method, etc. Pythoncommon tips and methods, friends in need can refer to the following
1. Three methods of reversing strings
1.1. Simulate the method in C++, define an empty string to achieve
By setting an empty string, and then traverse the string in the parameter from back to front, using string addition Merge into a new string
def reverse(text) : str = '' index = len(text) - 1 while index >= 0 : str += text[index] index -= 1 return str
1.2. Use the slicing method
This is a feature in Python. Slicing can take negative values. This is the method of using slicing. , set the step size to -1, thus achieving reverse sorting.
def reverse_1(text) : return text[::-1]
1.3. Using a list
Use the reverse method of the list, first convert the text into a list, then reverse it through the reverse method, and then connect it into characters through join string.
def reverse_2(text) : temp = list(text) temp.reverse() return ''.join(temp)
2. Use reduce
Use anonymous function and reduce()
def reverse_3(text) : return reduce(lambda x, y : y + x, text) print reverse_3("Hello")
3. Traverse the dictionary Four methods of
dict={"a":"apple","b":"banana","o":"orange"} print "##########dict######################" for i in dict: print "dict[%s]=" % i,dict[i] print "###########items#####################" for (k,v) in dict.items(): print "dict[%s]=" % k,v print "###########iteritems#################" for k,v in dict.iteritems(): print "dict[%s]=" % k,v print "###########iterkeys,itervalues#######" for k,v in zip(dict.iterkeys(),dict.itervalues()): print "dict[%s]=" % k,v
4. Three methods of traversing list
for key in lst : print key for i in range(len(lst)) : print lst[i] for index, key in enumerate(lst) : print key //index是list的索引
5. Method of dictionary sorting
The dictionary is sorted according to the value of value from large to small (default is sorted from small to small).
dic = {'a':31, 'bc':5, 'c':3, 'asd':4, 'aa':74, 'd':0} dict= sorted(dic.iteritems(), key=lambda d:d[1], reverse = True) print dict //输出的结果: [('aa', 74), ('a', 31), ('bc', 5), ('asd', 4), ('c', 3), ('d', 0)]
Let’s decompose the code below
print dic.iteritems() to get a list of [(key, value)].
Then use the sorted method, through the key parameter, to specify that the sorting is based on value, that is, the value of the first element d[1. reverse = True means that it needs to be flipped. The default is from small to large. If it is flipped, it will be from large to small.
Sort dictionary by key:
dic = {'a':31, 'bc':5, 'c':3, 'asd':4, 'aa':74, 'd':0} dict= sorted(dic.iteritems(), key=lambda d:d[0]) # d[0]表示字典的键 print dict #sorted中第三个可选参数为reverse, True表示从大到小排序 #默认reverse = False
The above is the detailed content of Some common Python methods compiled for your reference. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

Regarding the problem of removing the Python interpreter that comes with Linux systems, many Linux distributions will preinstall the Python interpreter when installed, and it does not use the package manager...

Pylance type detection problem solution when using custom decorator In Python programming, decorator is a powerful tool that can be used to add rows...

About Pythonasyncio...

Using python in Linux terminal...

Loading pickle file in Python 3.6 environment error: ModuleNotFoundError:Nomodulenamed...

Compatibility issues between Python asynchronous libraries In Python, asynchronous programming has become the process of high concurrency and I/O...

Error loading Pickle file in Python 3.6 environment: ModuleNotFoundError:Nomodulenamed...

The problem and solution of the child process continuing to run when using signals to kill the parent process. In Python programming, after killing the parent process through signals, the child process still...
