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  • react-whether提供执行if和else逻辑的简单声明方式。 安装 npm install --save react-whether 用 react-whether出口3个组成部分: Whether :逻辑块的根。 Match :匹配条件Whether为“ Whether的子项。 Else :...
  • ifwhether的区别PPT教案.pptx
  • ifwhether的区别

    千次阅读 2010-07-18 20:20:00
    ifwhether都可译为/"是否/",二者引导宾语从句时通常可以互相替换,口语中多用if代替whether。例如:Ask if/whether he plans to come to the meeting. 而以下几种情况中, 只能用whether: 1. 强调两...

    if和whether都可译为/"是否/",二者引导宾语从句时通常可以互相替换,口语中多用if代替whether。例如:Ask if/whether he plans to come to the meeting. 而以下几种情况中, 只能用whether:
    1. 强调两方面的选择,特别是句中有or not时。如:
    Let me know whether you can come or not.
    2. 宾语从句前置时。如:
    Whether this is true, I can/'t say.
    3. 引导主语、表语、同位语从句时。如:
    Whether the football game will be played depends on the weather. (主语从句)
    The question is whether he can do it. (表语从句)
    The question whether we should go with them must be decided at once. (同位语从句)

    4. 在介词之后作介词的宾语时。如:
    I haven/'t settled the question of whether I/'ll go back home.

    5. 在不定式前与不定式一起组成词组时。如:
    Whether to go or stay is still a question.

    6. 在discuss, decide 等动词后作宾语时。如:
    We discussed whether we should go there by plane.

    值得注意的是: if还可以引导条件状语从句,是/"假如;如果/"之意,而whether可以引导让步状语从句,是/"不管;无论/" 之意。如:
    If you ask him, he will help you.
    I shall go, whether you come with me or stay at home.

    一、if或whether引导宾语从句时,作“是否”讲,常放在动词ask 、see 、say 、know和find out等后面。一般情况下,两者常可换用,在口语中多用if。如:
    例1 Nobody knows whether (if) it will rain tomorrow. 没有人知道明天是否下雨。

    例2 Lucy asked whether (if) they had a cotton sweater .露西问他们是否有棉制的羊毛衣。

    二、if或whether引导宾语从句时,要注意三个方面,即连词、语序和时态。
    1 if或whether不能和that 或其它连词(副词)同时使用,也不能省去。如:
    例3 我不知道他今天是否会来。

    [误] I don’t know that if(whether) he will come here today .
    [正] I don’t know if(whether) he will come here today .
    例4他走过来看看猫是否出了毛病。

    误] He came to see what if (whether) there was wrong with his cat .

    [正] He came to see if (whether) there was wrong with his cat .

    2 if或whether引导的宾语从句时,虽具有疑问意义,但从句语序应用陈述句语序。如:

    例5 Did you know the way to the hospital ? The old woman asked me .

    The old woman asked me .if (whether) I knew the way to the hospital .老妇人问我是否知道去医院的路。

    3 if或whether引导的宾语从句应和主句的时态保持一致。即主句为一般现在时,从句用任一种时态;主句为一般过去时,从句则用过去时中的任一种时态。如:

    例6 I don’t know if (whether) he has come here . 我不知道他是否来过这儿。

    例7 Tom asked if (whether) I had read the book . 汤姆问我是否看过这本书 。

    三、if和whether的区别:

    1 在动词不定式之前只能用whether 。如:

    例8 I can’t decide whether to stay. 我不能决定是否留下。

    2 在whether …… or not 的固定搭配中。如:

    例9 I want to know whether it’s good news or not . 我想知道是否是好消息。

    3 在介词后,只能用whether。如:

    例10 His father is worried about whether he lose his work . 他的父亲担心是否会失去工作。

    4宾语从句放在句首表示强调时,只能用whether 。如:

    例11 Whether they can finish the work on time is still a problem . 他们是否能准时完成这项工作还是个问题。

    5用if会引起歧义时,只用whether。如:

    例12 Could you tell me if you know the answer ?

    这句话有两种意思:“你能告诉我是否知道答案吗?”或“如果你知道答案,请告诉我,好吗?”。如用whether可避免歧义。

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  • Ifwhether的区别 (含 讲解+习题+答案)之欧阳道创编.pdf
  • Ifwhether的区别 (含 讲解+习题+答案)之欧阳歌谷创作.pdf
  • 1.whether引导主语从句时,既可以直接位于句首,也可以位于句末;if引导主语从句时只能用于it作形式主语的从句中。  whether we need it is a ...在宾语从句中,当表示“是否”时,whether与if可以互换,但如果从句
         
      1.whether引导主语从句时,既可以直接位于句首,也可以位于句末;if引导主语从句时只能用于it作形式主语的从句中。
    
      whether we need it is a different matter.
      it is a different matter whether(if)we need it.


      2.在宾语从句中,当表示“是否”时,whether与if可以互换,但如果从句中有or not 时只能用whether 引导。

    i don’t know whether he will come or not.


      3.whether引导的从句可以充当介词宾语,if则不行。
      i worry about whether i hurt her feelings.


      4.whether引导的从句可以作名词的同位语,if则不行。

            the question whether we need it has not been decided.


      5.可能造成歧义时,用whether而不用if。
      please let me know whether you are coming.
      请告诉我你是否要来。(whether引导宾语从句)
      please let me know if you are coming.
      如果你要来,请告诉我。(if引导状语从句)



    from:http://www.jxteacher.com/xzs2011/column20717/59bc45a4-16a7-41f0-a6b4-d606a2aec1f5.html

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  • MATLAB数据类型

    千次阅读 多人点赞 2017-07-14 07:53:55
    Determine whether input is cell array of strings ischar Determine whether item is character array isfield Determine whether input is structure array field isfloat ...

    MATLAB 并不需要任何类型的声明或维度报表。 MATLAB 每当遇到一个新的变量名称,创建变量,并分配适当的内存空间。

    如果变量已经存在,则MATLAB替换以新的内容的原始内容,并分配新的存储空间,在必要的情况下。

    例如,

    Total = 42

    上述语句创建了一个名为“Total” 的 1-1 矩阵存储值42。

    MATLAB中可用的数据类型

    MATLAB 提供15个基本数据类型。每种数据类型的数据存储在矩阵或阵列的形式。这个矩阵的大小或阵列是一个最低 0-0,这可以长大为任何规模大小的矩阵或数组。

    下表显示了在 MATLAB 中最常用的数据类型:

    数据类型描述
    int88-bit signed integer
    uint88-bit unsigned integer
    int1616-bit signed integer
    uint1616-bit unsigned integer
    int3232-bit signed integer
    uint3232-bit unsigned integer
    int6464-bit signed integer
    uint6464-bit unsigned integer
    singlesingle precision numerical data
    doubledouble precision numerical data
    logicallogical values of 1 or 0, represent true and false respectively
    charcharacter data (strings are stored as vector of characters)
    cell arrayarray of indexed cells, each capable of storing an array of a different dimension and data type
    structureC-like structures, each structure having named fields capable of storing an array of a different dimension and data type
    function handleyiibaier to a function
    user classesobjects constructed from a user-defined class
    java classesobjects constructed from a Java class

    例子

    创建一个脚本文件,用下面的代码:

    str = 'Hello World!'
    n = 2345
    d = double(n)
    un = uint32(789.50)
    rn = 5678.92347
    c = int32(rn)

    上面的代码编译和执行时,它会产生以下结果:

    str =
    Hello World!
    n =
       2345
    d =
       2345
    un =
       790
    rn =
       5.6789e+03
    c =
       5679
    

    数据类型转换

    MATLAB 提供各种函数,用于从一种数据类型转换到另一种。下表显示的数据类型转换函数:

    函数目的/作用
    charConvert to character array (string)
    int2strConvert integer data to string
    mat2strConvert matrix to string
    num2strConvert number to string
    str2doubleConvert string to double-precision value
    str2numConvert string to number
    native2unicodeConvert numeric bytes to Unicode characters
    unicode2nativeConvert Unicode characters to numeric bytes
    base2decConvert base N number string to decimal number
    bin2decConvert binary number string to decimal number
    dec2baseConvert decimal to base N number in string
    dec2binConvert decimal to binary number in string
    dec2hexConvert decimal to hexadecimal number in string
    hex2decConvert hexadecimal number string to decimal number
    hex2numConvert hexadecimal number string to double-precision number
    num2hexConvert singles and doubles to IEEE hexadecimal strings
    cell2matConvert cell array to numeric array
    cell2structConvert cell array to structure array
    cellstrCreate cell array of strings from character array
    mat2cellConvert array to cell array with potentially different sized cells
    num2cellConvert array to cell array with consistently sized cells
    struct2cellConvert structure to cell array

    测定的数据类型

    MATLAB 提供各种函数标识数据类型的变量。

    下表提供了确定一个变量的数据类型的函数:

    函数目的/作用
    isDetect state
    isaDetermine if input is object of specified class
    iscellDetermine whether input is cell array
    iscellstrDetermine whether input is cell array of strings
    ischarDetermine whether item is character array
    isfieldDetermine whether input is structure array field
    isfloatDetermine if input is floating-yiibai array
    ishghandleTrue for Handle Graphics object handles
    isintegerDetermine if input is integer array
    isjavaDetermine if input is Java object
    islogicalDetermine if input is logical array
    isnumericDetermine if input is numeric array
    isobjectDetermine if input is MATLAB object
    isrealCheck if input is real array
    isscalarDetermine whether input is scalar
    isstrDetermine whether input is character array
    isstructDetermine whether input is structure array
    isvectorDetermine whether input is vector
    classDetermine class of object
    validateattributesCheck validity of array
    whosList variables in workspace, with sizes and types

    例子

    创建一个脚本文件,用下面的代码:

    x = 3
    isinteger(x)
    isfloat(x)
    isvector(x)
    isscalar(x)
    isnumeric(x)
     
    x = 23.54
    isinteger(x)
    isfloat(x)
    isvector(x)
    isscalar(x)
    isnumeric(x)
     
    x = [1 2 3]
    isinteger(x)
    isfloat(x)
    isvector(x)
    isscalar(x)
     
    x = 'Hello'
    isinteger(x)
    isfloat(x)
    isvector(x)
    isscalar(x)
    isnumeric(x)
    当运行该文件,它会产生以下结果:
    
    x =
         3
    ans =
         0
    ans =
         1
    ans =
         1
    ans =
         1
    ans =
         1
    x =
       23.5400
    ans =
         0
    ans =
         1
    ans =
         1
    ans =
         1
    ans =
         1
    x =
         1     2     3
    ans =
         0
    ans =
         1
    ans =
         1
    ans =
         0
    x =
    Hello
    ans =
         0
    ans =
         0
    ans =
         1
    ans =
         0
    ans =
         0


    展开全文
  • Python if,else和elif语句

    千次阅读 2020-09-12 13:36:51
    In this tutorial, we shall focus on Python if, else and elif statement. 在本教程中,我们将专注于Python的if,else和elif语句。 Decisions are one of the most important feature of any computer program. ...

    In this tutorial, we shall focus on Python if, else and elif statement.

    在本教程中,我们将专注于Python的if,else和elif语句。

    Decisions are one of the most important feature of any computer program. It basically helps to systematically and logically execute the program based upon the input of the user (sometimes) or other factors which lets the user receive the desired output depending upon the input.

    决策是任何计算机程序中最重要的功能之一。 它基本上有助于基于用户的输入(有时)或其他因素来系统地和逻辑地执行程序,这使用户可以根据输入来接收所需的输出。

    Decision-making can be provided by making use of branching structures and loops. These Branching structures helps in conditional programming. In this tutorial you will learn about branching structures.

    可以通过使用分支结构和循环来提供决策。 这些分支结构有助于条件编程。 在本教程中,您将学习分支结构。

    Python if语句 (Python if Statement)

    An if statement or an if block as it is commonly said, is useful to make decisions based on conditions in a program sometimes based on user input data.

    如通常所说的if语句或if块,对于基于程序中的条件(有时基于用户输入数据)进行决策很有用。

    An if block needs the keyword ‘if’ with a following condition and a set of statements to be executed in case the condition turns out to be True. A condition is mostly an expression which can be evaluated either to true or false.

    一个if块需要带有以下条件的关键字“ if”,并在条件变为True的情况下执行一组语句。 条件主要是可以被评估为true或false的表达式。

    Syntax

    句法

    if Condition:
    	statement 1
    	statement 2
    	statement n

    Example

    a=10
    if a>8: 
    	print("A is Greater than 8")

    Output

    输出量

    A is Greater than 8

    A大于8

    Here, a variable ‘a’ is initialized to 10. Then, an if block is used with the condition that checks whether a is greater than 8 or not. If it evaluates to be true, then the set of statements following that condition will be executed and then the program will come out of that particular block and execute the next set of statements.

    在这里,变量“ a”被初始化为10。然后,使用if块,条件是检查a是否大于8。 如果评估结果为true,则将执行该条件之后的语句集,然后程序将从该特定块中出来并执行下一组语句。

    Note: We generally use indentations to make the program look more readable that follows a much better logical approach. Here, it is important to use indentations as it helps to construct the if block in a logical manner.

    注意:我们通常使用缩进使程序看起来更具可读性,并且遵循更好的逻辑方法。 在此,使用缩进非常重要,因为它有助于以逻辑方式构造if块。

    Python if else语句 (Python if else Statement)

    The if-else condition is useful when you have multiple conditions to be evaluated in a program. Suppose you want to check for a particular condition and if that evaluates to false, you can then opt for another condition checking to evaluate it. This helps to produce a better output based on verification.

    如果在程序中要评估多个条件,则if-else条件很有用。 假设您要检查特定条件,如果该条件的值为假,则可以选择另一种条件检查以对其求值。 这有助于基于验证产生更好的输出。

    In this type of structure, the program will execute at least one of the blocks; either if block or else block.

    在这种类型的结构中,程序将执行至少一个块。 如果阻塞或否则阻塞。

    Note: You must use proper indentations in if-else structure and if you dont do so, you will get an error as the Python Interpreter wont be able to understand the difference between the if block and else block.

    注意:您必须在if-else结构中使用适当的缩进,如果不这样做,则会出现错误,因为Python解释器将无法理解if块和else块之间的区别。

    Syntax

    句法

    if Condition:
    	statement 1
    	statement 2
    	statement n
    else:
    	statement 1
    	statement 2
    	statement n

    Example

    a=10
    if a<8: 
    	print("A is Less than 8") 
    else: 
    	print("A is Greater than 8")

    Output

    输出量

    A is Greater than 8

    A大于8

    Here, first the variable a is initialized to 10. In the if block, the condition is checked whether it is less than 8 and it is evaluated to be false. The Python Interpreter now has to go to the else block so as to execute the else condition statements which is mandatory. So, this is better than a single if block as this provides a better informed output to the user.

    在此,首先将变量a初始化为10。在if块中,检查条件是否小于8,并将其评估为false。 Python解释器现在必须转到else块,以便执行必需的else条件语句。 因此,这比单个if块更好,因为这可以为用户提供更好的信息输出。

    Python if elif else语句 (Python if elif else Statement)

    Suppose, you need to check for multiple conditions, you cant do it with a single if Block or an if-else Block. The if-elif-else block comes in use when you want to comapare a variable or any object for that matter to multiple other values. You can add as many elif conditions you want. elif stands for else-if. Here, else block is optional.

    假设您需要检查多个条件,则无法使用单个if块或if-else块来做到这一点。 当您想将变量或与此相关的任何对象映射为多个其他值时,将使用if-elif-else块。 您可以添加任意多个elif条件。 elif代表else-if。 在这里,else块是可选的。

    Note: You must have a single condition that must evaluate to true otherwise it will go to the else Block. Whenever a condition evaluates to be true, the interpreter will execute that particular block and will then exit out of the if-elif-else structure and wont even check for any other succeeding conditions.

    注意:您必须具有一个条件,该条件的值必须为true,否则它将进入else块。 每当条件评估为真时,解释器将执行该特定块,然后退出if-elif-else结构,甚至不检查其他任何后续条件。

    Syntax

    句法

    if Condition 1:
    	statement 1
    	statement 2
    	statement n 
    elif Condition 2:
    	statement 1
    	statement 2
    	statement n 
    elif Condition 3:
    	statement 1
    	statement 2
    	statement n 
    else:
    	statement 1
    	statement 2
    	statement n

    Example

    a=4
    if a==1: 
    	print("A is 1")
    elif a==2: 
    	print("A is 2") 
    elif a==3: 
    	print("A is 3") 
    elif a==4: 
    	print("A is 4") 
    elif a==5: 
    	print("A is 5") 
    else: 
    	print("A is not between 1 and 5")

    Output

    输出量

    A is 4

    A是4

    Here, we have used comparison operator == to compare values of the variable a in the condition. Suppose the first condition evaluated to be true, then the control will execute that particular block and will go directly out of the if-elif-else Structure.

    在这里,我们使用了比较运算符==来比较条件中变量a的值。 假设第一个条件评估为true,则控件将执行该特定块,并将直接退出if-elif-else结构。

    If you found any mistake in above Python if, else and elif statement tutorial then mention it by commenting below.

    如果您在上述Python if,else和elif语句教程中发现任何错误,请通过在下面的注释中提及它。

    翻译自: https://www.thecrazyprogrammer.com/2015/08/python-if-else-and-elif-statement.html

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  • whether....or not 引导的宾语从句

    千次阅读 2019-10-05 16:33:41
     even if   即使   whether or not  无论是...或..,是否 Pattern:  Donot u know him?  Yesterday We went to the museum and  nowhere else .  Would u like to eat/drink anything else ?  I ...
  • 安装又出问题了。。configuration时候出现checking whether the C compiler works... no 排查:1.g++,apt-get install g++,已安装;  2.看config.log文件,没看懂;
  • 介绍if函数的基本用法
  • logback.xml if 条件判断

    千次阅读 2020-11-05 14:07:11
    For example, to check whether the property “k” is defined you would write isDefined(“k”) Similarly, if you need to check whether a property is null, the isNull() method is provided. Example: is...
  • Python if else elif

    万次阅读 2020-07-14 20:04:52
    Python if else and elif are keywords for conditional logic in the program. In this tutorial we are going to learn about python if, else and elif. Previously we learned about Python Operators and Prece...
  • Indicate whether to send a cookie in a cross-site request by specifying its SameSite attribute Because a cookie’s SameSite attribute was not set or is invalid, it defaults to SameSite=Lax, which ...
  • Linux创建Oracle时,在Prerequis ite Checks时出现如下...[oracle@*** oracle]$ dd if=/dev/zero of=/home/swap bs=1024 count=8010460 dd: failed to open '/home/swap': Permission denied [oracle@*** oracle]$...
  •  (3)、有可能存在服务器没有准确获取文件修改时间,或者代理服务器时间不一致等情形。 然而,Etag是服务器自动生成或者由开发者生成的对应资源在服务器端的唯一标识符,能够更加准确的控制缓存。 四、...
  • I’m not sure if… 我...也可以说”I’m not sure whether…”。支持范例 I’m not sure if the book you mentioned is still available. 我不知道你说的那本书还有没有了。 I’m not sure if he is qualified enoug
  • Whether Thread Pool is Needed for You?

    千次阅读 2016-04-25 22:53:31
    if ( NULL != m_pSyncObject ) { m_pSyncObject->Lock(); } } /** * Destructor. * * @param Nil * @return Nil * @exception Nil * @see Nil * @since 1.0 */ ~AutoLock() { if ( ...
  • If Controller ,Jmeter官方介绍:...The If Controller allows the user to control whether the test elements below it (its children)...
  • This is a prerequisite condition to test whether sufficient total swap space is available on the system. (more details) Expected Value  : 15.64GB (1.6403472E7KB) 16400000 Actual Value  : ...
  • Given two binary trees, check whether they are identical or not. Analyze: we first compare the roots of these two trees, if they are the same, we continue to compare the root of the
  • whether作为“是否”讲却没有疑问意味 从可行性上进行分析: 我们知道一般疑问句和特殊疑问句,其句子,都是助动词(be,will,could,do等)提前到主语之前了。 把一个陈述句的助动词提前,变成一般疑问句,那么这...
  • ovs的netdev, ofproto以及dpif etc.

    千次阅读 2016-10-10 02:08:11
    If there is no match, the datapath passes the packet up to ofproto-dpif, which maintains the full OpenFlow flow table. If the packet matches in this flow table, then ofproto-dpif executes its actions ...
  • freemarker写select组件报错总结(四)

    千次阅读 2014-06-26 00:21:34
    Check whether you have a well-formed if-else block. at freemarker.core.FMParser.generateParseException(FMParser.java:4702) at freemarker.core.FMParser.jj_consume_token(FMParser.java:4573) at ...
  • checking how to hardcode library paths into programs... immediate checking whether stripping libraries is possible......checking if libtool supports shared libraries... yes checking whether to build...
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