python map visualization

Map function: Prototype: Map (function, sequence), which maps a list to another list, How to use: def f (x): Return x**2 L = Range (1,10) Map (f,l) OUT[3]: [1, 4, 9, 16, 25, 36, 49, 64, 81] Reduce function Prototype: reduce (function, sequence, startvalue), which is to summarize a list as an output,How to use: def f2 (x, y): Return X+y Reduc

image results The spider is simple enough to use the Python third-party library requests and BEAUTIFULSOUP4, the code is concise enough, suitable for learning. The core code is as follows: Kongjiespider crawled pictures are saved in a local folder: Kongjie Results The flight attendant crawlers are stacked on my github: https://github.com/ychenracing/Spiders/tree/ Master/kongjiexxx crawler did not say, go to GitHub to see. Have a surprise. The final s

Map (f, Itera) # Use F (x) for each elementlambda x:x**2>>> l = map (sq,[-1,0,1,2,-3])>>> list (l) [1, 0, 1, 4, 9]Of course, you can also pass in two parameters:Lambda x, y:x + y>>> l = map (lambda x, y:x + y, [1, 3, 5, 7, 9], [2, 4, 6, 8, ten ])>>> list (l) [3, 7, 11, 15, 19]Reduce (f (x), Itera) # x1 The result F (x1) Continuation and the next element of the

(1) Lambda A lambda is a python that creates an anonymous function in the form of the following syntax: Lambda [arg1[, arg2, ... argn]]: expressionUse examples: #使用法一 fun = lambda x,y:x+y print Fun (1,2) #输出结果为: 3 #使用法二 print (lambda x,y:x+y) (1,2) # Output: 3 #上面法一和法二相当于: def func_1 (x, y): return x + y print func_1 (1, 2) (2) Map () Map (function, sequenc

The Map,filter and reduce function arguments in Python must all be a function and a parameter. The difference is: When the map executes, a function is typically executed once for each element in the parameter or list, returning a list of the functions that were executed after the individual parameters. Map (functio

Map function: Prototype: Map (function, sequence), which maps a list to another list,How to use:def f (x):Return x**2L = Range (1,10)Map (f,l)OUT[3]: [1, 4, 9, 16, 25, 36, 49, 64, 81] Reduce function Prototype: reduce (function, sequence, startvalue), which is to summarize a list as an output,How to use:def f2 (x, y):Return X+yReduce (f1,l)OUT[

(1) Lambda Lambda is a useful syntax in Python that allows you to quickly define a single-line minimum function. Similar to a macro in C, it can be used wherever a function is needed.The basic syntax is as follows:函数名 = lambda args1,args2,...,argsn : expressionFor example:Add = Lambda x,y:x + yPrint (ADD) (2) Filter filterfunction is equivalent to a filter, the function prototype is: filter(function,sequence) , for each element in t

, Cmap=cm.gist_earth, vert_exag=0.1, blend_mode= ' soft ')Surf = Ax.plot_surface (X, Y, Z, rstride=1, cstride=1, Facecolors=rgb,Linewidth=0, Antialiased=false, Shade=false)Plt.show () #最后渲染出你好看的三维图吧 (2333333333333333333)PS: The python I used is anaconda integrated, avoids installing Matplot (233333333333)Anaconda Install Gdal, installation method gray often simple win+r cmd into the command window and then enter the

1. Apply the ' function ' method to each element in the ' iterable ' of the iterated function and return the result as a list.Here's an example:>>> def add100 (x):... return x+100...>>> hh = [11,22,33]>>> Map (ADD100,HH)[111, 122, 133]As the document says: Add100 the elements in HH and returns a list of the results.2. If an additional iterative parameter is given, the ' function ' is applied to the element ' parallel ' in each iteration parameter. (tr

Map ()Return an iterator-Applies function to every item of iterable, yielding the resultsFor example:A = map (lambda x:x**2, [I/z ])printfor in a])Results:[1, 4, 9]Or:A = map (lambda x,y:x+y, [],[1,2])print for in a])Results:[2, 4]filter(function, iterable)Construct a iterator from those elements of iterable for which function returns TRUE. If function None is, a

1. Use map and reduce write a str2float function to convert a string ‘123.456‘ into a floating-point number 123.456 : fromFunctoolsImportReducedefStr2Num (s):return{'0': 0,'1': 1,'2': 2,'3': 3,'4': 4,'5': 5,'6': 6,'7': 7,'8': 8,'9'8 {}[s]defStr2float (s):if '.' inchS:#splits the string s into a list types = S.split ('.') #divide by decimal point, calculate and add separately returnReduceLambdaX, Y:x*10+y,

The map () function, which receives two parameters, one is a function, the other is a sequence, and map () acts on each element of the sequence in turn, and returns the result as a new sequence;AA = [1, 2, 3, 4, 5]print ("", List (map (Lambda a:a * A, aa)))#Map-result = [1, 4, 9, 16, 2 5] The filter () function,

At work you need to convert the elements in the List object (list type) to the set type, which requires access to the elements after the conversion is complete.The first step is to use the map method to convertdata = [[1, 3, 4], [2, 3, 5], [1, 2, 3, 5], [2, 5]]print (data) # [[1, 3, 4], [2, 3, 5], [1, 2, 3, 5], [2, 5]]-------------- -----------data = map (set,data) print (data) # 　Step two, visit the mapPr

elements of the list x to build a dictionary, the key value is the list of each element, value is None4. Get (key) to find value based on key5. Hash_key (x) find if the dictionary contains a key value x6. Update (x) updating another dictionary with one dictionary7, Popitem () delete the last element and return8, Pop (key) delete the key value corresponding to the element9. Items () Converts the dictionary to a list and returns10, Iteritems () Convert dictionary to list, return iterator11. Key (