efficiency, this is not considered here, only to illustrate the actual bit plane layering algorithm principle.The results of section 6,7,8 are as follows: Another application of the bit plane layering is that in image compression, from the results of the above layered graphs, we only need to use the higher-order layers to reconstruct the original artwork, which means that you can use a smaller bit layer than the original (such as 4 layers, which reduces the storage volume by 50%).The algorit
indicate the type, can also not indicate the type, var iarray3 = [5]int32{1, 2, 3, 4, 5} is also completely no problem.
(2) The capacity and length of the array are the same. Both the CAP () function and the Len () function output the capacity (that is, the length) of the array. such as:
Copy the code code as follows:
Func Test6 () {Iarray4: = [5]int32{6, 7, 8, 9, 10}Fmt. Println (Len (IARRAY4))Fmt. Println (Cap (IARRAY4))}
The output is all 5.
(3) Use:
Copy the code code as follows:
F
negative, the number from the back forward;If not 1, it is the number of steps to jump, 1 means to go one step, jump 0 steps;If the first parameter is not filled in, it is automatically set to the first parameter, which is either the index maximum or the index minimum based on the positive or negative judgment of the third parameterA few simple examples First define: S=[1,2,3,4,5,6,7,8,9,10]s[0:5:1] Results: [1,2,3,4,5]s[0,5,2]s[:5:2] The result is: [1,3,5]s[5:0:-1] Results: [5,4,3,2,1]s[9::-1]
What's the object slicing:C + + in the process of converting a derived class to a base class, a part of the derived class is not received by the base class, leaving only the object of the base class size.A slice of a value call:#include 650) this.width=650; "src=" Http://s1.51cto.com/wyfs02/M02/80/B2/wKioL1dEBsPw8WpkAAAjKs-tdsk046.png "title=" 2.PNG " alt= "Wkiol1debspw8wpkaaajks-tdsk046.png"/>650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M00/80/BE/wKioL1dECJPS0QYsAAAo58KSjzc275.png "ti
Python Sequence Modification, hash, and Slicing,
Vector: User-defined sequence type
We will use the combination mode to implement the Vector class without using inheritance. The vector component is stored in the floating-point array, and the method required to implement an immutable flat sequence is also implemented.
The Vector version 1st should be compatible with the Vector2d class defined in the previous chapter.
Vector version 1st: compatible w
Python learning Day 4 function slicing iterative list generator,
Define functions
Def my_abs (x): # evaluate the absolute value of the my_abs Function
If x> = 0:
Return x
Else:
Return-x
Def nop (): # Empty Function
Pass # placeholder
Parameter check
>>> My_abs (1, 2)
Traceback (most recent call last ):
File "
TypeError: my_abs () takes exactly 1 argument (2 given) # incorrect number of parameters
>>> My_abs ('A') # The parameter type is incorrect a
Addobject:value];}NSLog (@ "Sortedkeys%@", Sortedkeys);NSLog (@ "Sortedvalues%@", sortedvalues);1 Creating a large dictionary that manages color objectsNsmutabledictionary *newcolordic = [[Nsmutabledictionary alloc]init];2 traversing the Color data dictionaryFor (NSString *key in Colordic) {Gets the corresponding valueNSString *value = [Colordic Valueforkey:key];Encapsulation of objectsColor *color = [[Color Alloc]initwithname:key colorvalue:value];Get first letterNSString *first = [[Key substr
The prototype of the slice operator in Python is[Start:stop:step]That is: [Start index: End index: Step value]Start index: Same as other languages, starting from 0. Sequence from left to right, index of first value is 0, last one is-1 End index: The slice operator is taken to the index and does not contain the value of the index. Step value: The default is one after the other, if it is 2, it means to take one operation. When the step value is positive, it is taken from left to right and, if nega
First look at the following code:>>a=np.arange (10)>>aArray ([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])>>A[-7]Array ([3, 4, 5, 6, 7, 8, 9])>>A[-7-1:-1]Array ([2, 3, 4, 5, 6, 7, 8])>>a[-7-1:-2]Array ([2, 3, 4, 5, 6, 7])>>A[-7-2:-1]Array ([1, 2, 3, 4, 5, 6, 7, 8])>> A[-7-2:]Array ([1, 2, 3, 4, 5, 6, 7, 8, 9])As can be seen from the above example, A[-n] is to select the last n elements of a array to form an array. A[-N-X:-Y] indicates that x elements are taken forward on the formed A[-n] array, and that the Y
To get a partial element of a list or tuple:L = [' Michael ', ' Sarah ', ' Tracy ', ' Bob ', ' Jack ']l[0:3][' Michael ', ' Sarah ', ' Tracy ']l[:3][' Michael ', ' Sarah ', ' Tracy ']l[- 2:][' Bob ', ' Jack ']l[-2:-1][' bob ']l = List (range) l[0,1,2,3,4,5,..., 99]l[:10:2][0,2,4,6,8]l[::5][0, 5, 10, 15, 20, 1, 2, 3,., 99]//Copy a list (0,1,2,3) [: 3] (0,1,2) ' ABCDEF ' (95]l[:][0), +----------- G ' [: 3] ' ABC ' ' ABCDEFG ' [:: 2] ' ACEG ' Basic Python Tutorial--
One: Takes the first character of a stringprint "Hello" [0] indicates the first character in the output stringprint "Hello" [-1] indicates the last character in the output stringTwo: String segmentationprint "Hello" [1:3]#第一个参数表示原来字符串中的下表#第二个阐述表示分割后剩下的字符串的第一个字符 subscript in the original stringThis sentence is a bit verbose, directly look at the output:ElThree: Several special cases(1) print "Hello" [: 3] Start with the first character intercept(2) print "Hello" [0:] intercept from the first char
() >>> d = {' A ': 1, ' B ': 2, ' C ': 3} >>> for key in D: ... Print (key) ... a c b >>> for ch in ' ABC ': ... print (CH) ... a b c python the built-in enumerate function can turn a list into an index-element pair, This allows you to iterate both the index and the element itself in the FOR loop: >>> for I, value in enumerate ([' A ', ' B ', ' C '): ... 0 A 1 B 2 C >>> from collections Import iterabl
Slicing Slice theory knowledge
It is not an array by itself, it points to the underlying array
As an alternative to programming arrays, you can associate local or all of the underlying array
As a reference type
You can create directly or get a build from the underlying array
Use Len () to get the number of elements, and the cap () to get the capacity
General use make () to create
If multiple slice point to the same und
ai how Ai how to use slicing tool to crop graphics?
1, the first step must be to open the AI software
2. If you want to cut the material on the interface to a picture in PNG format with no background, so the first step is to hide the rest of the material, including the background, as shown below, take the red box as an example, if you want to cut out the red box, then first hide the red.
3. After hiding, select the Red box and sel
character of the variable is G, there will never be a match. *m string.
Two. "Percent" operator:1. Example:2. Explanation:The difference between "percent" and "%" is that '% ' is greedy, meaning it matches the longest string that meets the criteria. So in the example, file%%.* will start matching from the right, the longest match is. Jpg.txt, and then delete it. So the value of the variable name is sample.Three. "#" operator1. Example:Example 1Example 22. Explanation:Example 1:file#*. is t
(1) (http://www.pythontab.com/html/2013/pythonjichu_0128/182.html)
First, analyze the slice operation from the principle:
A slice of the list, inside of which is calling the __getitem__,__setitem__,__delitem__ and slice functions. The slice function is also associated with the range () function.
The key passed to the slice is a special slice object. The object has attributes that describe the orientation of the requested slice, for example:
1 2 3 4
A = [1, 2, 3, 4, 5, 6] x = A [
In Python, we define a string, as shown below.
Define a string in Python and assign it to a variable.
We can access a single character by subscript, as with all languages, subscript starting from 0 (= = I think I write a good brain.)
At this point, we can use slicing to intercept a part of our defined string.
There are two ways to use slices: 1. Simple slices without step size
The syntax format is this:
1. First define a grid string, such as Hebe, a
Map Slicing Tool CollectionRecently more interested in map tile generation, search for a number of useful tools, found that the following three kinds have been more mature, complete documentation. Of course there are a lot of special tools or better and no find, welcome to add.Maptiler (gdal2tiles GUI version): The current version is Alpha, can be cut into the TMS standard format tiles, and generate Openlayer and Google Map call example. Support for a
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