what if condition

Now only special cases are mentioned:1, a variable, such as N1=null2, a variable, such as N1, does not assign a value3, a variable, such as n1,n1= ""4, a variable, such as n1,n1= ""5, a variable, such as N1,N1=0,N2 not assigned value6, for the above

Shell if-B Returns True when file exists and is a block file-C Returns True when file exists and is a character-D returns True when pathname exists and is a directory-E Returns True when a file or directory specified by pathname is present-F Returns

[-A file] is true if file exists.[-B file] True if file exists and is a block special file.[-C file] True if file exists and is a word special.[-D file] True if file exists and is a directory.[-E File] True if file exists.[-F file] True if file

Write operations scripts through if statements and variables,A key to install the lamp environment of the script;A key source installation lamp script, the first decomposition of the various functions of the script;Print Menu:1) Install Apache Web

One: Python basics1. File suffix name:. py2, Python2 to read Chinese in the file header write:-*-coding:utf8-*-3. Input uses n as a variable, substituting a value for a changen = input (' Enter user name: ') waits for the user to enter a value, the

First, the program implementation process diagram:Second, the code implementation:OnePublic static void Main (string[] args) { int beernumber=;String beername="Bottles"; While (beernumber100) {System.out.println (beernumber+":"

Conditional tests can be returned if they are true or false.Use double quotation marks when comparing strings, and if the variables are not there may be an error.Permissions, who execute on who has permissionA script is a stack of commands that you

A python conditional statement determines which block of code is executed by judging the execution result of one or more conditional statements.The IF statement in Python is used for control program execution in the basic form:If judging

Testing and judging of shell scripts1. TestingGrammar:[operator condition] = = Test operator condition1) test file-level directoryType of File:F, FileLs-l # #只查看字段的第一个字符, file "-"D, CatalogueLs-ldL, Link fileLs-lC, character deviceLs-l/dev/ttyB,

Boolean expressionAn expression with a value of true or false . Non-Boolean expressions can also be converted to a Boolean value if desired, but the following rules are followed: All objects are treated as true. The string is treated as

Purpose: To determine whether a file (test.gz.txt) suffix is a zipCorrect command: if [[${filename} =~ ^test.*zip$]]Here are a few things to keep in mind: use [[]] for its related usage see link 1; =~ is connected, I am in use, did not pay

Content summary: In CSS layout, also often use IE Hack. If IE plays a very big role!Keywords: Div CSS IE HackWhat does the IF IE mean? The following is a list of some common hack control statements in CSS.As IE, if conditional comments using memo,

We have explained a multi-choice elseif statement. Although this statement can be used for multiple judgments, many if statements need to be written during use, which makes the readability of our program inconvenient, to avoid too many if statements

This article mainly introduces the if Condition Statement in the basic Javascript tutorial. if is a common syntax, you can refer to it as follows: If (coditon) statement1 (else statement2) Coditon can be any expression, or even a Boolean value,

1. Determine the number of digitsConsole.Write ("Please enter a number"); intA=int. Parse (Console.ReadLine ()); if(a>Ten) { if(a -) {Console.WriteLine ("This is a two-digit number"); }

PHP Code Reuse I have an if condition (which is a combination of many expressions) and is used on many pages, but the condition is changing at any time, such as:if (condition)Statement How can I reuse the code for this condition? Thank you so much!

For CSS layout, refer to the IF condition annotation of IE to use memo.   All except Ie can be recognized all IE identifiable only ie5.0 can recognize only ie5.0 and ie5.5 can be recognized both ie5.0 and ie5.0 can be recognized only IE6

If condition judgment for Linuxshell scriptsIF condition judgment1. Basic Syntax:If [command]; thenStatements that meet this conditionFi2. Extended Syntax:If [command]; thenStatements that meet this conditionElif [command]; thenStatements that meet

Shell script IF condition judgment and judgment condition details, shellifPreface: No matter what programming language, conditional judgment is indispensable. SHELL is no exception. if list thendo something hereelif list thendo another thing

If condition judgment of Linux shell script, linuxshellIF condition judgment1. Basic Syntax:If [command]; thenStatements that meet this conditionFi 2. Extended Syntax: If [command]; then Statements that meet this condition Elif [command];