    &gt; grepl(&quot;^[^_]+_1&quot;,s)
    [1] FALSE
    &gt; grepl(&quot;^[^_]+_2&quot;,s)
    [1] TRUE

basically, look for everything at the beginning except `_`, and then the `_2`.

+1 to @Ananda_Mahto for suggesting `grepl` instead of `grep`.

I think it&#39;s worth answering the generic question &quot;R - test if string contains string&quot; here.

For that, use the 
[grep function][1].

    # example:
    &gt; if(length(grep(&quot;ab&quot;,&quot;aacd&quot;))&gt;0) print(&quot;found&quot;) else print(&quot;Not found&quot;)
    [1] &quot;Not found&quot;
    &gt; if(length(grep(&quot;ab&quot;,&quot;abcd&quot;))&gt;0) print(&quot;found&quot;) else print(&quot;Not found&quot;)
    [1] &quot;found&quot;

  [1]: 127.0.0.1:27675/library/base/html/grep.html







How can I get the request url in Scrapy&#39;s `parse()` function? I have a lot of urls in `start_urls` and some of them redirect my spider to homepage and as result I have an empty item. So I need something like `item[&#39;start_url&#39;] = request.url` to store these urls. I&#39;m using the BaseSpider.

Scrapy get request url in parse

Is there any way to add an element that is an Angular directive with jQuery methods like `append()` and have Angular do its compilation/linking to make it work as though you&#39;d included the directive in the first place?

Example:

    app.directive(&#39;myAngularDirective&#39;, [function () {
        ...
        // Lots of stuff in here; works when used normally but not when added via jQuery
    });

    $(&quot;body&quot;).append(&quot;&lt;my-angular-directive /&gt;&quot;);

It currently just appends an empty DOM element called &quot;my-angular-directive,&quot; but Angular doesn&#39;t kick in and do its magic. 

How to add DOM Elements (Angular directives) via jQuery&#39;s .append()?

I have an R string, with the format

    s = `&quot;[some letters and numbers]_[a number]_[more numbers, letters, punctuation, etc, anything]&quot;`

I simply want a way of checking if `s` contains `&quot;_2&quot;` in the first position. In other words, after the first `_` symbol, is the single number a &quot;2&quot;? How do I do this in R?

I&#39;m assuming I need some complicated regex expresion?

Examples:

    39820432_2_349802j_32hfh = TRUE

`43lda821_9_428fj_2f = FALSE` (notice there is a `_2` there, but not in the right spot)

R - test if first occurrence of string1 is followed by string2

I have an R string, with the format
<pre><code class="hljs language-css">s = `"[some letters and numbers]_[a number]_[more numbers, letters, punctuation, etc, anything]"`
</code></pre>
I simply want a way of checking if <code>s</code> contains <code>"_2"</code> in the first position. In other words, after the first <code>_</code> symbol, is the single number a "2"? How do I do this in R?
I'm assuming I need some complicated regex expresion?
Examples:
<pre><code class="hljs language-ini">39820432_2_349802j_32hfh = TRUE
</code></pre>
<code>43lda821_9_428fj_2f = FALSE</code> (notice there is a <code>_2</code> there, but not in the right spot)

I have managed to find online how to overlay a normal curve to a histogram in R, but I would like to retain the normal &quot;frequency&quot; y-axis of a histogram. See two code segments below, and notice how in the second, the y-axis is replaced with &quot;density&quot;. How can I keep that y-axis as &quot;frequency&quot;, as it is in the first plot.

**AS A BONUS:** I&#39;d like to mark the SD regions (up to 3 SD) on the density curve as well. How can I do this? I tried `abline`, but the line extends to the top of the graph and looks ugly.

    g = d$mydata
    hist(g)
![enter image description here][1]

    g = d$mydata
    m&lt;-mean(g)
    std&lt;-sqrt(var(g))
    hist(g, density=20, breaks=20, prob=TRUE, 
         xlab=&quot;x-variable&quot;, ylim=c(0, 2), 
         main=&quot;normal curve over histogram&quot;)
    curve(dnorm(x, mean=m, sd=std), 
          col=&quot;darkblue&quot;, lwd=2, add=TRUE, yaxt=&quot;n&quot;)
![enter image description here][2]

See how in the image above, the y-axis is &quot;density&quot;. I&#39;d like to get that to be &quot;frequency&quot;.

  [1]: http://i.stack.imgur.com/7bl5b.png
  [2]: http://i.stack.imgur.com/1dfiE.png

Overlay normal curve to histogram in R

As a silly toy example, suppose

    x=4.5
    w=c(1,2,4,6,7)

I wonder if there is a simple R function that finds the index of the closest match to `x` in `w`.  So if `foo` is that function, `foo(w,x)` would return `3`.  The function `match` is the right idea, but seems to apply only for exact matches.  

Solutions [here][1] (e.g. `which.min(abs(w - x))`, `which(abs(w-x)==min(abs(w-x)))`, etc.) are all `O(n)` instead of `log(n)` (I&#39;m assuming that `w` is already sorted).


  [1]: http://r.789695.n4.nabble.com/Find-the-closest-value-in-a-list-or-matrix-td838131.html

Find closest value in a vector with binary search

I believe my dataframe is okay and my code is okay.  In fact, I have eliminated parts of the dataframe and most of the graphing code to make things as basic as possible.  But still, I get:

    Error in .Call.graphics(C_palette2, .Call(C_palette2, NULL)) : 
      invalid graphics state

What is wrong here?  Here is the data: 


     date	trt	var	val
    1/8/2008	cc	sw5	0.2684138
    1/8/2008	cc	sw15	0.2897586
    1/8/2008	cc	sw5	0.2822414
    2/8/2008	cc	sw5	0.2494583
    2/8/2008	cc	sw5	0.2692917
    2/8/2008	cc	sw15	0.2619167
    2/8/2008	cc	sw5	0.204375
    3/8/2008	cc	sw5	0.2430625
    3/8/2008	cc	sw5	0.2654375
    3/8/2008	cc	sw5	0.2509583
    3/8/2008	cc	sw5	0.2055625
    1/8/2008	ccw	sw15	0.2212414
    1/8/2008	ccw	sw5	0.3613448
    1/8/2008	ccw	sw5	0.2607586
    2/8/2008	ccw	sw5	0.2087917
    2/8/2008	ccw	sw15	0.3390417
    2/8/2008	ccw	sw5	0.2436458
    2/8/2008	ccw	sw5	0.290875
    3/8/2008	ccw	sw5	0.20175
    3/8/2008	ccw	sw15	0.328875
    3/8/2008	ccw	sw5	0.2328958
    3/8/2008	ccw	sw5	0.2868958

When I work with this data, I specify dates like this:

    df&lt;-df[order(as.Date(df$date,format=&quot;%d/%m/%Y&quot;)),,drop=FALSE]

and here I want to make a scatterplot:

    ggplot(data = df,aes(x = date,y = val)) + 
     geom_point(aes(group = trt))





Persistent invalid graphics state error when using ggplot2

When I plot a bar graph in ggplot2 I would like to reduce the space between the bottom of the bars and the x-axis to 0, yet keep the space above the bars and the plot box.  I have a hack to do it below.  It&#39;s dirty and I want to be clean again.  Is there a way to achieve this behavior without the dirty little hack?

**Default (desired space above but don&#39;t want space below bars):**

    ggplot(mtcars, aes(x=as.factor(carb))) + 
        geom_bar()

![enter image description here][1]

 **Use expand (undesired 0 space above but got the 0 space below bars):**
   
    ggplot(mtcars, aes(x=as.factor(carb))) + 
        geom_bar() + 
        scale_y_continuous(expand = c(0,0)) 
   
![enter image description here][2]

**Dirty Hack (I like it but its.. well, dirty):**

    
    ggplot(mtcars, aes(x=as.factor(carb))) + 
        geom_bar() + 
        scale_y_continuous(expand = c(0,0)) +
        geom_text(aes(x=1, y=10.3, label=&quot;Stretch it&quot;), vjust=-1)

![enter image description here][3]


  [1]: http://i.stack.imgur.com/avtvl.png
  [2]: http://i.stack.imgur.com/zbWSy.png
  [3]: http://i.stack.imgur.com/ZI00w.png

ggplot2 bar plot, no space between bottom of geom and x axis keep space above

I&#39;m trying to understand the definition of `scale` that R provides. I have data (`mydata`) that I want to make a heat map with, and there is a VERY strong positive skew. I&#39;ve created a heatmap with a dendrogram for both `scale(mydata)` and `log(my data)`, and the dendrograms are different for both. Why? What does it mean to scale my data, versus log transform my data? And which would be more appropriate if I want to look at the dendrogram illustrating the relationship between the columns of my data?

Thank you for any help! I&#39;ve read the definitions but they are whooping over my head.  

Understanding `scale` in R

I would like to match the following text `sometext12345_text` using the below regex. 

I&#39;m using this in one of my selenium tests.

    String expr = &quot;//*[contains(@id, &#39;sometext[0-9]+_text&#39;)]&quot;;
    driver.findElement(By.xpath(expr));

It doesn&#39;t seem to work though. Can somebody help?

How to use regex in XPath &quot;contains&quot; function

I&#39;ve got a list of elements, say, integers and I want to check if my variable (another integer) is one of the elements from the list. In python I&#39;d do:

    my_list = [1,2,3,4] # elements
    my_var = 3 # my variable
    my_var in my_list # returns boolean

How to do that in C++? I thought of using `std::list`, but I can find no `find` method in it. I can see such method in `std::set` structure.

More deeply, the problem is that my program is given some unique ids (a list, a set, whatever) and I iterate over a long list of input data (ids) and check if they are included in the list (boolean value returned for each iteration step). And I&#39;m not sure how should I do that in C++.

Check if element is in the list (contains)

I have a two dimensional (or more) pandas DataFrame like this:

    &gt;&gt;&gt; import pandas as pd
    &gt;&gt;&gt; df = pd.DataFrame([[0,1],[2,3],[4,5]], columns=[&#39;A&#39;, &#39;B&#39;])
    &gt;&gt;&gt; df
       A  B
    0  0  1
    1  2  3
    2  4  5

Now suppose I have a numpy array like `np.array([2,3])` and want to check if there is any row in `df` that matches with the contents of my array. Here the answer should obviously true but eg. `np.array([1,2])` should return false as there is no row with both 1 in column A and 2 in column B.

Sure this is easy but don&#39;t see it right now.

Pandas: Check if row exists with certain values

In Java we have `HashSet&lt;Integer&gt;`, I need similar structure in Python to use contains like below:

    A = [1, 2, 3]
    S = set()
    S.add(2)
    for x in A:
        if S.contains(x):
            print &quot;Example&quot;

Could you please help?

Contains of HashSet&lt;Integer&gt; in Python

I am trying to check if a specific item (value of a property) exists in a array of objects, but could not find out any solution. Please let me know, what i am missing here.

            class Name {
                var id : Int
                var name : String
                init(id:Int, name:String){
                    self.id = id
                    self.name = name
                }
            }
            
            var objarray = [Name]()
            objarray.append(Name(id: 1, name: &quot;Nuibb&quot;))
            objarray.append(Name(id: 2, name: &quot;Smith&quot;))
            objarray.append(Name(id: 3, name: &quot;Pollock&quot;))
            objarray.append(Name(id: 4, name: &quot;James&quot;))
            objarray.append(Name(id: 5, name: &quot;Farni&quot;))
            objarray.append(Name(id: 6, name: &quot;Kuni&quot;))
            
            if contains(objarray[&quot;id&quot;], 1) {
                println(&quot;1 exists in the array&quot;)
            }else{
                println(&quot;1 does not exists in the array&quot;)
            }

Content Type	Original Author	Original Content on Stackoverflow
Question	StanLe	View Question on Stackoverflow
Solution 1 - R	Julián Urbano	View Answer on Stackoverflow
Solution 2 - R	Timothée HENRY	View Answer on Stackoverflow

R - test if first occurrence of string1 is followed by string2

R Problem Overview

R Solutions

Solution 1 - R

Solution 2 - R

How to add DOM Elements (Angular directives) via jQuery's .append()?

Scrapy get request url in parse

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