conditional | 易学教程

R - dplyr - mutate_if multiple conditions

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问题 I want to mutate a column based on multiple conditions. For example, for each column where the max is 5 and the column name contains "xy", apply a function. df <- data.frame( xx1 = c(0, 1, 2), xy1 = c(0, 5, 10), xx2 = c(0, 1, 2), xy2 = c(0, 5, 10) ) > df xx1 xy1 xx2 xy2 1 0 0 0 0 2 1 5 1 5 3 2 10 2 10 df2 <- df %>% mutate_if(~max(.)==10, as.character) > str(df2) 'data.frame': 3 obs. of 4 variables: $ xx1: num 0 1 2 $ xy1: chr "0" "5" "10" $ xx2: num 0 1 2 $ xy2: chr "0" "5" "10" #function

SQL conditional statement

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问题 I'm trying to create a conditional statement in an ORACLE sql code I have a function in java that takes 2 parameters. getchildren(child1,child2) ..this function's parameters are used to create a query statement public ResultSet getchildren(String Child1, String child2) throws SQLException { stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY); query ="select * from table1 if child1 is not null and child2 is null { where child1 = 1 } else if child2 is not

SQL conditional statement

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C# 特性 Attribute

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https://www.runoob.com/csharp/csharp-attribute.html 理解：特性就是一个标签，可以给程序中的元素添加一些信息，在程序运行时就可以访问元素的这些信息，程序就可以通过这些信息进行其他操作。当然特性在编译期就存在了，所有编译器也可以通过这些特性信息进行条件编译。 1、定义： (1) 特性（Attribute）是用于在运行时传递程序中各种元素（比如类、方法、结构、枚举、组件等）的行为信息的声明性标签。 (2) 是一个标签，用于传递元素的信息。 (3) 元素：类、方法、结构、枚举、组件等。 2、内容： (1) 通过放置在它所应用的元素前面的方括号（[ ]）来描述的。 (2) 特性（Attribute）用于添加元数据，如编译器指令和注释、描述、方法、类等其他信息。 (3) .Net 框架提供了两种类型的特性：预定义特性和自定义特性。 3、语法： (1) 语法规则： [attribute(positional_parameters, name_parameter = value, ...)] element (2) 特性（Attribute）的名称和值是在方括号内规定的，放置在它所应用的元素之前。 positional_parameters 规定必需的信息； name_parameter 规定可选的信息。 4、预定义特性： (1) .Net

Should I use Perl's conditional ? : operator as a switch / case statement or instead of if elsif?

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问题 Perl has a conditional operator that is the same a C's conditional operator. To refresh, the conditional operator in C and in Perl is: (test) ? (if test was true) : (if test was false) and if used with an lvalue you can assign and test with one action: my $x= $n==0 ? "n is 0" : "n is not 0"; I was reading Igor Ostrovsky's blog on A neat way to express multi-clause if statements in C-based languages and realized this is indeed a "neat way" in Perl as well. For example: (edit: used Jonathan

Xslt how to style conditional odd/even rows

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问题 I've an html table written using xslt transformation that looks like this <table> <xsl:for-each select="someNode"> <xsl:if test="testThis"> <tr>  <td>something</td> </tr> </xsl:if> <tr>  <td>this is always displayed</td> </tr> <xsl:if test="testThis2"> <tr>  <td>something 2</td> </tr> </xsl:if> .... </xsl:for-each> <tr> <!--

Bind Image.Source according to Boolean without a converter?

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问题 I want to have an image bound to a boolean and have the source of the image to depend on the boolean value i.e. true source="image1" false source="image2" I was wondering if there is a way to do it inline without need for a converter. 回答1: You can create a style on the Image which uses a DataTrigger to swap the image source depending on a binding. In this example the image changes depending on the value of a boolean called simply "Value". <Image Width="16"> <Image.Style> <Style TargetType="{x

conditional javascript code not executing

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问题 Does anyone know why this code might not work? touchmove and touchend do not execute only touchstart because that's a seperate event and function :) $('input').live("touchstart", function (e) {$(this).addClass('click')}); $('input').live("touchmove,touchend", function (e) { if (e.type == 'touchmove'){ $('.temp').removeClass('temp'); $('.click').removeClass('click'); } else{var inputvalue = $(this).val() $('input[value="' + inputvalue + '"] + label').css({ '-webkit-transition': 'opacity 0.3s

What's the difference between if and elseif?

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问题 This should be a simple question. I have a simple if/else statement: <?php // TOP PICTURE DEFINITIONS if ( is_page('english') ) { $toppic = 'page1.png'; } if ( is_page('aboutus') ) { $toppic = 'page1.png'; } if ( is_page('newspaper') ) { $toppic = 'page1.png'; } else { $toppic = 'page1.png'; } ?> Is there a difference from ^^^ to this: <?php // TOP PICTURE DEFINITIONS if ( is_page('english') ) { $toppic = 'page1.png'; } elseif ( is_page('aboutus') ) { $toppic = 'page1.png'; } elseif ( is_page

One-line if vs && in JavaScript [closed]

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问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 4 years ago . Is there any meaningful difference between condition && console.log("this may run"); and if (condition) console.log("this may run); If not, which is a best practice? 回答1: You should use the second. Your code should say what it means. That is what is meant by writing "semantic