• Summary of variables in DOS batch file


    The variables in batch processing can be divided into two categories: system variable and custom variable. System variable: Their values are automatically assigned by the system according to the pre-defined conditions, that is, these variable systems have defined values for them.We don’t need to assign values to him. We just need to call and list […]

  • Naming rules for variables, functions and classes


    1, naming is worthy of the name.When naming, we must consider its display meaning and context, and do not think that it is a waste of time to spend on variable naming. Of course, if your program is very short, you don’t need to think so much about it. Just bury your head in writing […]

  • Is the python collection a variable summary


    A set is an unordered variable sequence. The elements in a collection must be hash-able, that is, immutable data types. Empty set a=set() Note that a={} creates an empty dictionary. Set — Variable sets. Elements in a collection can be added or deleted dynamically. Frozenset — an immutable set. Elements in a collection are immutable. […]

  • Instance code for initialization of Perl constants, multidimensional arrays and variables


    Example 1: Copy codeThe code is as follows: #!/usr/bin/perluse strict; use warnings;my $test = “asdf”;print “${test}_test2\n”;#constantuse constant {    AAA => “aaa”,    BBB=> “bbb”,    MIN_TOTAL => 12,    SCORE_PASS => 90,    SCORE_RED => 70,};print AAA;print SCORE_PASS;#two dimesion arraysmy @steps = (      [“aaa”, “aaavalue”],      [“bbb”,”bbbvalue”],      [“ccc”,”cccvalue”]);print “\n”;foreach my $i (0 .. $#steps){  print “$steps[$i][0]:$steps[$i][1]\n”;} Code 2: Copy codeThe […]

  • Perl uses variables as handles


    Copy codeThe code is as follows: #!/usr/bin/perl -wuse strict;use warnings;use FileHandle;my %fh;my @array = (1..10);for(1..5){        open $fh{$_},”>$_.txt” or die;}for(1..5){# print $fh {$} “$__ n”; error        $fh{$_}->print( “$_\n” );# For functions in FileHandle (my $h = $fh {$}; print $h “$__ n”; } Note: The above errors are due to the fact that <> is not a […]

  • Linux Definition Variable Script Sharing


    In this paper, we share Linux variable definition script for your reference. The details are as follows. There are two pieces of code that are basically the same, but the variables are changed, and the others are unchanged, but the results are different in the execution process. Code 1: vi back.sh #backup import file,such as […]

  • Do you really know the variables and types?


    Guide reading Variables and types are learningJavaScriptThe first thing you come into contact with, but what seems to be the simplest thing often hides a lot of knowledge that you don’t understand or are prone to make mistakes, such as the following questions: JavaScriptWhat is the specific storage form of variables in memory? 0.1+0.2Why not […]

  • Go Language Learning Packages and Variables


    Preface This paper mainly introduces the relevant contents about go language package and variables, and shares them for your reference and study. Let’s see the detailed introduction together. I. The Concept of Package Package is an indispensable part of go language. It is defined on the first line of each go source code in the […]

  • Method for shell for loop, loop variable value to pay other shell scripts


    This article focuses on how to write for loops in the shell, and takes loop variables as parameters of the next shell script. Shell for loop: # The first is similar to C and Java. for ((i=1; i<=100; i ++)) do echo $i done # The second way of writing in application for i in […]

  • On the Scope of Variables in Shell Cycle


    Recently, a shell script has been implemented. Simply speaking, it reads all the lines from the file and writes them into a file. The key code is as follows. path_all=”” cat $1 | while read line do if [ “$path_all” == “” ];then path_all=$line else path_all=$path_all,$line fi done echo $path_all > $one_file The result of […]

  • How to set the highlight of vs2013 variable or function with the same name?


    What should I do when the computer is installed with help and the function of Visual Studio 2013 with highlighted display is blocked? We can use “Disable Reference Highlighting”. Let’s take a look at the detailed tutorial below. Software Name: Visual Studio Community 2013 Official Chinese Free Edition Software size: 1.62MB Update time: 2014-11-19 1. […]

  • When the use of the Perl variable $/ resolves the context as a row pattern, $/ defines what distinguishes rows


    By default, it’s obvious that lines are distinguished by n, which is also called a newline character.When a sequence is read by line, the newline character is the standard. The contents of the read strawberry 1.gb file are as follows:LOCUS JX118024 460 bp DNA linear PLN 25-SEP-2012 DEFINITION Fragaria vesca subsp. americana RNA polymerase beta […]