1. HadoopIt would is impossible to talk about open source data analytics without mentioning Hadoop. This Apache Foundation project have become nearly synonymous with big data, and it enables large-scale distributed processi Ng of extremely large data sets. A survey conducted by TDWI and SAS found this nearly percent of enterprises expected to has Hadoop clusters in product Ion by the end of 2016.However, it should be noted, the Hadoop on its own doesn ' t enable data analytics. It ' s usually pa
object (Function-object), and this property is completely replaced if the variable object already has a property of the same name. VD all variable declaration (VAR, variabledeclaration) A property of the variable object, which consists of the variable name and the undefined value, if the variable name is the same as the formal parameter or function that has already been declared, The variable declaration does not interfere with such properties that already exist. }};Code embodiesaler
comments):int a = 123; // a是整数类型变量a = "ABC"; // 错误:不能把字符串赋给整型变量This is why dynamic languages are more flexible than static languages.Do not equate an equal sign of an assignment statement with a mathematical equal sign. For example, the following code:x = 10x = x + 2If mathematically understood x = x + 2 that is not tenable in any case, in the program, the assignment statement evaluates the right expression first x + 2 , obtains the result 12 , and a
true. In Python, equals = is an assignment statement, you can assign any data type to a variable, the same variable can be repeatedly assigned, and can be different types of variables, for example: a = 123 # A is an integer print (a) a = ' ABC ' # A changed to a string print (a) This type of variable itself is called Dynamic language, which corresponds to static language. Static languages must specify the variable type when defining the variable, and if the type does not match, an error is give
executed.This makes it very easy to traverse a list or tuple.Example of a scene exampleAfter the class exam, the teacher to statistical average results, 4 students are known to list the results are as follows:L = [75, 92, 59, 68]Please use the For loop to calculate the average score.L = [75, 92, 59, 68]sum = 0.0for i in L: sum = sum + iprint sum / 4Example TwoPrint 0,2,4,6,8.for i in range(0,10,2): print("loop",i)While loopAnother loop that differs from the For loop is the while loop, which doe
that Android developer can use in their workflow:
Instant Run -for every developer who loves faster build speeds. Make changes and see them appear live in your running app. With many build/run accelerations ranging from VM hot swapping toUtm_campaign=android_launch_studio_040716utm_source=anddevutm_medium=blog#instant-run ">warm Swapping app resources, Instant Run would save your time every day.
Android Emulator -The new Emulator runs ~3x faster than Android ' s previous Emulator, and wit
right alignment. -Indicates left alignment. ' is a space that fills a space on the left side of a positive number to align with a negative number. 0 means using 0 padding.Width indicates display widthsPrecision indicates the precision after the decimal pointLike what:Print ("%+10x") print ("%04d"% 5) print ("%6.3f"% 2.3)The width above, precision is two integers. We can use * to dynamically substitute these two quantities. Like what:Print ("%.*f"% (4
variable is a stringAnswer = True #Answer A variable is a Boolean valueTrueIn Python, the equals sign = is an assignment statement that assigns any data type to a variable, the same variable can be repeatedly assigned, and can be a variable of different types , for example:123 # a是整数print(a)a = ‘ABC‘ # a变为字符串print(a)This type of variable itself is called Dynamic language, which corresponds to static language. Static languages must specify the variable type when defining the variable, and
This section reads as follows:
Print output
Using numbers
Using strings
Working with lists
Judging using conditions
Using loops
Print outputIf we use the command-line interactive environment, you can output some numbers, strings, and variables directly if you need to use the print function in the. py file, for example:
print(‘Hello Python‘)
Using numbersA simple number contains integers and floating-point numbers, which can be used to
characters 10x, after the current position after inserting 3! , 3a! W moves forward one word (the cursor stops at the beginning of the word), and if it is at the end of the line, go to the start of the next line. This command is fast and can replace the L command.b Move backward one word 2b move backwards 2 wordsE, with W, except that the cursor stops at the tail of the word.GE, with B, the cursor stops at the end of the word.^ Moves to the first non
replaced by W.K Move up one characterJ Move down one characterThe above four commands can be used with the number, such as 20J is to move down 20 lines, 5h is to move 5 characters to the left, in vim, many commands can be used with the number, such as delete 10 characters 10x, after the current position after inserting 3! , 3a! W moves forward one word (the cursor stops at the beginning of the word), and if it is at the end of the line, go to the sta
complete.: Set Wrapscan re-search, when searching to the head or end of the file, return to continue the search, by default open.Replace commandThe RA replaces the current character with a, when the period character is the character of the cursor.s/old/new/replace new with old, replacing the first match of the current rows/old/new/g replace new with old, replacing all occurrences of the current row%s/old/new/replace new with old, replacing the first match of all rows%s/old/new/g replace new wit
10x, after the current position after inserting 3! , 3a! W moves forward one word (the cursor stops at the beginning of the word), and if it is at the end of the line, go to the start of the next line. This command is fast and can replace the L command.b Move backward one word 2b move backwards 2 wordsE, with W, except that the cursor stops at the tail of the word.GE, with B, the cursor stops at the end of the word.^ Moves to the first non-whitespace
with Word2! For example, search for vbird between 100 and 200 rows and replace it with Vbird:": 100,200s/vbird/vbird/g". ( common )
: 1, $s/word1/word2/g
Look for the word1 string from the first line to the last line and replace the string with Word2! ( common )
: 1, $s/word1/word2/gc
Look for the word1 string from the first line to the last line and replace the string with Word2! and display the prompt character before the substitution to the user to confi
complete.: Set Wrapscan re-search, when searching to the head or end of the file, return to continue the search, by default open.Replace commandThe RA replaces the current character with a, when the period character is the character of the cursor.s/old/new/replace new with old, replacing the first match of the current rows/old/new/g replace new with old, replacing all occurrences of the current row%s/old/new/replace new with old, replacing the first match of all rows%s/old/new/g replace new wit
to replace! Common
Delete, copy and paste on
X, X
In one line of words, X is the backward deletion of a character (equivalent to the [Del] key), and X is to delete a character (equivalent to [backspace], which is the backspace) (common)
Nx
N is a number that continuously deletes n characters backwards. For example, I want to delete the 10 characters consecutively, "10x".
Dd
Delete
, when the period character is the character of the cursor.s/old/new/replace new with old, replacing the first match of the current rows/old/new/g replace new with old, replacing all occurrences of the current row%s/old/new/replace new with old, replacing the first match of all rows%s/old/new/g replace new with old, replacing all occurrences of the entire file: 10,20 s/^//g adds four spaces before each line in line 10th to indent.DDP swaps the line that the cursor is in and immediately below it.
/word1/word2/g
N1 and N2 are numbers. Look for the string word1 between N1 and N2, and replace the string with Word2! For example, search for vbird between 100 and 200 rows and replace it with Vbird:": 100,200s/vbird/vbird/g". Common
: 1, $s/word1/word2/g
Look for the word1 string from the first line to the last line and replace the string with Word2! Common
: 1, $s/word1/word2/gc
Look for the word1 string from the first line to the last line and replac
complete.: Set Wrapscan re-search, when searching to the head or end of the file, return to continue the search, by default open.Replace commandThe RA replaces the current character with a, when the period character is the character of the cursor.s/old/new/replace new with old, replacing the first match of the current rows/old/new/g replace new with old, replacing all occurrences of the current row%s/old/new/replace new with old, replacing the first match of all rows%s/old/new/g replace new wit
) whether need to replace! Common
Delete, copy and paste on
X, X
In one line of words, X is the backward deletion of a character (equivalent to the [Del] key), and X is to delete a character (equivalent to [backspace], which is the backspace) (common)
Nx
N is a number that continuously deletes n characters backwards. For example, I want to delete the 10 characters consecutively, "10x".
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