I would like to scrape data from the tweet's volume chart on https://bitinfocharts.com into a data file using R. I'm a newbie in this world and after seeking a lot on the web I have no other choice than to ask for your help. I found the same question in the forum but it's for python (How to Scrape data from chart on https://bitinfocharts.com)
The chart in question is the following: https://bitinfocharts.com/comparison/decred-tweets.html#alltime
I'm looking for a data table with each date and the respective number of tweets for that day as the columns.
I hope your experience will help me
This piece of code should help extract the data that you need:
library('rvest')
library('stringr')
url <- 'https://bitinfocharts.com/comparison/decred-tweets.html#alltime'
webpage <- read_html(url)
res <- str_match(webpage, 'new Dygraph\\(document.getElementById\\(\"container\\"\\),\\s*(.*?)\\s*, \\{labels')
res[,2]
After you do that you should parse the res[,2] and transform it according to your needs.
The new Dyagraph part comes from the page source. If you search for it in the page source (view-source:https://bitinfocharts.com/comparison/decred-tweets.html in your browser) you will notice it. Basically the website creates the graph based on this data.
To parse the matrix you need to first remove the "new Date("") parts of the string and then parse the full string using a json library.
Here is the complete code that should help you with that:
library('rvest')
library('stringr')
library('jsonlite')
url <- 'https://bitinfocharts.com/comparison/decred-tweets.html#alltime'
webpage <- read_html(url)
res <- str_match(webpage, 'new Dygraph\\(document.getElementById\\(\"container\\"\\),\\s*(.*?)\\s*, \\{labels')
res[,2] <- gsub("new Date\\(", "", res[,2])
res[,2] <- gsub("\\)", "", res[,2])
document <- fromJSON(txt=res[,2])
document
print(document[1, 1])
print(document[1, 2])
Related
I'm attempting web scraping. Before posting my question, I looked up several similar questions such as this, and this. However, I still get stuck in my problem.
Speicifically, I'm trying to extract the listed prices on a second-hand cars website. # In case you are unable to see the data because you're not a registered user of this website, I also attached the screenshot of this website's html elements:
the screen shot.
The code I executed are:
library(httr)
library(XML)
url <- "https://www.sahibinden.com/vasita?query_text_mf=alfa+romeo+giulietta&query_text=alfa+romeo+giulietta"
htmlresponse <- GET(url)
htmlcontent <- content(htmlresponse, as="text")
parsedhtml <- htmlParse(htmlcontent, asText = TRUE)
# The above is just following the conventions, and seems okay.
prices <- xpathSApply(doc = parsedhtml, path = "//div/td[#class='searchResultsPriceValue']", fun = xmlValue)
# This command returned me an empty list.
Can someone have a look and give me some advices? Thank you very much!
There are 2 parts of my questions as I explored 2 methods in this exercise, however I succeed in none. Greatly appreciated if someone can help me out.
[PART 1:]
I am attempting to scrape data from a webpage on Singapore Stock Exchange https://www2.sgx.com/derivatives/negotiated-large-trade containing data stored in a table. I have some basic knowledge of scraping data using (rvest). However, using Inspector on chrome, the html hierarchy is much complex then I expected. I'm able to see that the data I want is hidden under < div class= "table-container" >,and here's what I've tied:
library(rvest)
library(httr)
library(XML)
SGXurl <- "https://www2.sgx.com/derivatives/negotiated-large-trade"
SGXdata <- read_html(SGXurl, stringsASfactors = FALSE)
html_nodes(SGXdata,".table-container")
However, nothing has been picked up by the code and I'm doubt if I'm using these code correctly.
[PART 2:]
As I realize that there's a small "download" button on the page which can download exactly the data file i want in .csv format. So i was thinking to write some code to mimic the download button and I found this question Using R to "click" a download file button on a webpage, but i'm unable to get it to work with some modifications to that code.
There's a few filtera on the webpage, mostly I will be interested downloading data for a particular business day while leave other filters blank, so i've try writing the following function:
library(httr)
library(rvest)
library(purrr)
library(dplyr)
crawlSGXdata = function(date){
POST("https://www2.sgx.com/derivatives/negotiated-large-trade",
body = NULL
encode = "form",
write_disk("SGXdata.csv")) -> resfile
res = read.csv(resfile)
return(res)
}
I was intended to put the function input "date" into the “body” argument, however i was unable to figure out how to do that, so I started off with "body = NULL" by assuming it doesn't do any filtering. However, the result is still unsatisfactory. The file download is basically empty with the following error:
Request Rejected
The requested URL was rejected. Please consult with your administrator.
Your support ID is: 16783946804070790400
The content is loaded dynamically from an API call returning json. You can find this in the network tab via dev tools.
The following returns that content. I find the total number of pages of results and loop combining the dataframe returned from each call into one final dataframe containing all results.
library(jsonlite)
url <- 'https://api.sgx.com/negotiatedlargetrades/v1.0?order=asc&orderby=contractcode&category=futures&businessdatestart=20190708&businessdateend=20190708&pagestart=0&pageSize=250'
r <- jsonlite::fromJSON(url)
num_pages <- r$meta$totalPages
df <- r$data
url2 <- 'https://api.sgx.com/negotiatedlargetrades/v1.0?order=asc&orderby=contractcode&category=futures&businessdatestart=20190708&businessdateend=20190708&pagestart=placeholder&pageSize=250'
if(num_pages > 1){
for(i in seq(1, num_pages)){
newUrl <- gsub("placeholder", i , url2)
newdf <- jsonlite::fromJSON(newUrl)$data
df <- rbind(df, newdf)
}
}
I'm stuck on this one after much searching....
I started with scraping the contents of a table from:
http://www.skatepress.com/skates-top-10000/artworks/
Which is easy:
data <- data.frame()
for (i in 1:100){
print(paste("page", i, "of 100"))
url <- paste("http://www.skatepress.com/skates-top-10000/artworks/", i, "/", sep = "")
temp <- readHTMLTable(stringsAsFactors = FALSE, url, which = 1, encoding = "UTF-8")
data <- rbind(data, temp)
} # end of scraping loop
However, I need to additionally scrape the detail that is contained in a pop-up box when you click on each name (and on the artwork title) in the list on the site.
I can't for the life of me figure out how to pass the breadcrumb (or artist-id or painting-id) through in order to make this happen. Since straight up using rvest to access the contents of the nodes doesn't work, I've tried the following:
I tried passing the painting id through in the url like this:
url <- ("http://www.skatepress.com/skates-top-10000/artworks/?painting_id=576")
site <- html(url)
But it still gives an empty result when scraping:
node1 <- "bread-crumb > ul > li.activebc"
site %>% html_nodes(node1) %>% html_text(trim = TRUE)
character(0)
I'm (clearly) not a scraping expert so any and all assistance would be greatly appreciated! I need a way to capture this additional information for each of the 10,000 items on the list...hence why I'm not interested in doing this manually!
Hoping this is an easy one and I'm just overlooking something simple.
This will be a more efficient base scraper and you can get progress bars for free with the pbapply package:
library(xml2)
library(httr)
library(rvest)
library(dplyr)
library(pbapply)
library(jsonlite)
base_url <- "http://www.skatepress.com/skates-top-10000/artworks/%d/"
n <- 100
bind_rows(pblapply(1:n, function(i) {
mutate(html_table(html_nodes(read_html(sprintf(base_url, i)), "table"))[[1]],
`Sale Date`=as.Date(`Sale Date`, format="%m.%d.%Y"),
`Premium Price USD`=as.numeric(gsub(",", "", `Premium Price USD`)))
})) -> skatepress
I added trivial date & numeric conversions.
I belive your main issue is that the site requires a login to get the additional data. You should give that (i.e. logging in) a shot using httr and grab the wordpress_logged_inXXXXXXX… cookie from that endeavour. I just grabbed it from inspecting the session with Developer Tools in Chrome and that will also work for you (but it's worth the time to learn how to do it via httr).
You'll need to scrape two additional <a … tags from each table row. The one for "artist" looks like:
Pablo Picasso
You can scrape the contents with:
POST("http://www.skatepress.com/wp-content/themes/skatepress/scripts/query_artist.php",
set_cookies(wordpress_logged_in_XXX="userid%XXXXXreallylongvalueXXXXX…"),
encode="form",
body=list(id="pab_pica_1881"),
verbose()) -> artist_response
fromJSON(content(artist_response, as="text"))
(The return value is too large to post here)
The one for "artwork" looks like:
Les femmes d′Alger (Version ′O′)
and you can get that in similar fashion:
POST("http://www.skatepress.com/wp-content/themes/skatepress/scripts/query_artwork.php",
set_cookies(wordpress_logged_in_XXX="userid%XXXXXreallylongvalueXXXXX…"),
encode="form",
body=list(id=576),
verbose()) -> artwork_response
fromJSON(content(artwork_response, as="text"))
That's not huge but I won't clutter the response with it.
NOTE that you can also use rvest's html_session to do the login (which will get you cookies for free) and then continue to use that session in the scraping (vs read_html) which will mean you don't have to do the httr GET/PUT.
You'll have to figure out how you want to incorporate that data into the data frame or associate it with it via various id's in the data frame (or some other strategy).
You can see it call those two php scripts via Developer Tools and it also shows the data it passes in. I'm also really shocked that site doesn't have any anti-scraping clauses in their ToS but they don't.
I am a beginner in scraping data from website. It seems difficult for me to interpret the structure of html using XML or other packages.
Can anyone help me to download the data from this website?
http://wszw.hzs.mofcom.gov.cn/fecp/fem/corp/fem_cert_stat_view_list.jsp
It is about the investment from China. The character set is in Chinese.
What I've tried so far:
library("rvest")
url <- "http://wszw.hzs.mofcom.gov.cn/fecp/fem/corp/fem_cert_stat_view_list.jsp"
firm <- url %>%
html() %>%
html_nodes(xpath='//*[#id="Grid1MainLayer"]/table[1]') %>%
html_table()
firm <- firm[[1]] head(firm)
You can try with the function in the XML package called readHTMLTable that should download all the tables in the page and already format it into a data.frame.
library(XML)
all_tables = readHTMLTable("http://wszw.hzs.mofcom.gov.cn/fecp/fem/corp/fem_cert_stat_view_list.jsp")
Then since there is only one table in the page you linked it should be enough to get the first element so:
target_table = all_tables[[1]]
I need to fetch a certain part of data from multiple Wikipedia pages. How can I do that using WikipediR package? Or is there some other better option for the same. To be precise, I need only the below marked part from all the pages.
How can I get that? Any help would be appreciated.
Can you be a little more specific as to what you want? Here's a simple way to import data from the web, and specifically from Wikipedia.
library(rvest)
scotusURL <- "https://en.wikipedia.org/wiki/List_of_Justices_of_the_Supreme_Court_of_the_United_States"
## ********************
## Option 1: Grab the tables from the page and use the html_table function to extract the tables you're interested in.
temp <- scotusURL %>%
html %>%
html_nodes("table")
html_table(temp[1]) ## Just the "legend" table
html_table(temp[2]) ## THE MAIN TABLE
Now, if you want to import data from multiple pages that have essentially the same structure, but maybe just change by some number or something, please try this method.
library(RCurl);library(XML)
pageNum <- seq(1:10)
url <- paste0("http://www.totaljobs.com/JobSearch/Results.aspx?Keywords=Leadership<xt=&Radius=10&RateType=0&JobType1=CompanyType=&PageNum=")
urls <- paste0(url, pageNum)
allPages <- lapply(urls, function(x) getURLContent(x)[[1]])
xmlDocs <- lapply(allPages, function(x) XML::htmlParse(x))