Get values from children class while web scraping - html

I want to get list of Phase state from site. I make such code:
library("rvest")
library("magrittr")
url <- 'https://energybase.ru/en/oil-gas-field/index'
read_html(url) %>%
html_nodes(".info")%>%
html_children()%>%
html_children()
and I got:
[1] <small>City</small>
[2] <div class="value">Игарка</div>
[3] <small>Phase state</small>
[4] <div class="value">нефтегазовое</div>
[5] <small>Извлекаемые запасы A+B1+B2+C1</small>
[6] <div class="value">479.10 mln. tons</div>
[7] <small>City</small>
[8] <div class="value">Тазовский</div>
[9] <small>Phase state</small>
[10] <div class="value">газонефтяное</div>
[11] <small>Извлекаемые запасы A+B1+B2+C1</small>
[12] <div class="value">422.00 mln. tons</div>
[13] <small>City</small>
[14] <div class="value">Лянтор</div>
[15] <small>Phase state</small>
[16] <div class="value">нефтегазоконденсатное</div>
[17] <small>Извлекаемые запасы A+B1+B2+C1</small>
[18] <div class="value">380.00 mln. tons</div>
[19] <small>City</small>
[20] <div class="value">Тобольск</div>
I want to get all notes after
<div class="value">
the result should be:
нефтегазовое
газонефтяное
нефтегазоконденсатное
and so on. What function should I use to solve my problem?

You can use
read_html(url) %>%
html_nodes(".col-md-8:nth-child(2) .value") %>%
html_text
to get
[1] "нефтегазовое" "газонефтяное" "нефтегазоконденсатное" "нефтяное"
[5] "нефтяное" "нефтегазовое" "нефтяное" "нефтяное"
[9] "нефтяное" "нефтегазоконденсатное" "нефтегазоконденсатное" "нефтяное"
[13] "нефтегазоконденсатное" "нефтегазоконденсатное" "нефтяное" "нефтяное"
[17] "газонефтяное" "нефтегазоконденсатное" "нефтяное" "нефтегазовое"
A very good tool to get the right css-selector (.col-md-8:nth-child(2) .value) is https://selectorgadget.com/ - here the screenshot for your example:

You could just pull from the dropdown options then you get the unique list without repeats. Depends if you want full list with repeats or not.
library(rvest)
library(magrittr)
phases <- (read_html('https://energybase.ru/en/oil-gas-field/index') %>%
html_nodes('#fieldsearch-phase option') %>%
html_text())[-1]

Related

Recognizing and Keeping Elements Containing Certain Patterns in a List

I want to try and webscrape my own Stackoverflow Profiles! By this I mean, get an html link of every question I have ever asked:
https://stackoverflow.com/users/18181916/antonoyaro8
https://math.stackexchange.com/users/1024449/antonoyaro8
I tried to do this follows:
library(rvest)
library(httr)
library(XML)
url<-"https://stackoverflow.com/users/18181916/antonoyaro8?tab=questions&sort=newest"
page <-read_html(url)
resource <- GET(url)
parse <- htmlParse(resource)
links <- list(xpathSApply(parse, path="//a", xmlGetAttr, "href"))
I tried to pick up on a pattern and noticed that all links with questions have some number - so I tried to write a code that checks if elements in the list contain a number and keep these links:
rv <- c("1", "2", "3", "4", "5", "6", "7", "8", "9", "0")
final <- unique (grep(paste(rv,collapse="|"),
links, value=TRUE))
But I don't think I am doing this correctly - apart from the messy formatting, the final file is returning links that do not contain any numbers at all.
Can someone please show me how to webscrape these links properly, and then repeat this for all pages (e.g. https://stackoverflow.com/users/18181916/antonoyaro8?tab=questions&sort=newest, https://stackoverflow.com/users/18181916/antonoyaro8?tab=questions&sort=newest&page=2, https://stackoverflow.com/users/18181916/antonoyaro8?tab=questions&sort=newest&page=3)
Worse come to worst, if I can do it for one of these pages, I can manually copy/paste the code for all pages and proceed that way.
Thank you!
The output is a list of length 1. We need to extract ([[) the element before applying the grep
unique (grep(paste(rv,collapse="|"),
links[[1]], value=TRUE))
Note that the rv includes numbers 0 to 9 and it can match a digit if it is present anywhere in the link. If the intention is to subset the digits following the questions
grep("questions/\\d+", links[[1]], value = TRUE)
-output
[1] "/questions/72859976/recognizing-and-keeping-elements-containing-certain-patterns-in-a-list"
[2] "/questions/72843570/combing-two-selections-together"
[3] "/questions/72840913/selecting-rows-from-a-table-based-on-a-list"
[4] "/questions/72840624/even-out-table-in-r"
[5] "/questions/72840548/creating-a-dictionary-reference-table"
[6] "/questions/72837147/sequentially-replacing-factor-variables-with-numerical-values"
[7] "/questions/72822951/scanning-and-replacing-values-of-rows-in-r"
[8] "/questions/72822781/alternative-to-do-callrbind-data-frame-for-combining-a-list-of-data-frames"
[9] "/questions/72738885/referencing-a-query-in-another-query"
[10] "/questions/72725108/defining-cte-common-table-expressions-in-r"
[11] "/questions/72723768/creating-an-id-variable-on-the-spot"
[12] "/questions/72720013/selecting-data-using-conditions-stored-in-a-variable"
[13] "/questions/72717135/effecient-ways-to-append-sql-results-in-r"
...
If there are multiple pages, add the page= with paste or sprintf
urls <- c(url, sprintf("%s&page=%d", url, 2:3))
out_lst <- lapply(urls, function(url)
{
page <-read_html(url)
resource <- GET(url)
parse <- htmlParse(resource)
links <- list(xpathSApply(parse, path="//a", xmlGetAttr, "href"))
grep("questions/\\d+", links[[1]], value = TRUE)
})
-output
> out_lst
[[1]]
[1] "/questions/72859976/recognizing-and-keeping-elements-containing-certain-patterns-in-a-list"
[2] "/questions/72843570/combing-two-selections-together"
[3] "/questions/72840913/selecting-rows-from-a-table-based-on-a-list"
[4] "/questions/72840624/even-out-table-in-r"
[5] "/questions/72840548/creating-a-dictionary-reference-table"
[6] "/questions/72837147/sequentially-replacing-factor-variables-with-numerical-values"
[7] "/questions/72822951/scanning-and-replacing-values-of-rows-in-r"
[8] "/questions/72822781/alternative-to-do-callrbind-data-frame-for-combining-a-list-of-data-frames"
[9] "/questions/72738885/referencing-a-query-in-another-query"
[10] "/questions/72725108/defining-cte-common-table-expressions-in-r"
[11] "/questions/72723768/creating-an-id-variable-on-the-spot"
[12] "/questions/72720013/selecting-data-using-conditions-stored-in-a-variable"
[13] "/questions/72717135/effecient-ways-to-append-sql-results-in-r"
[14] "/questions/72710448/removing-files-from-global-environment-with-a-certain-pattern"
[15] "/questions/72710203/r-sql-is-the-default-option-sampling-with-replacement"
[16] "/questions/72695401/allocating-max-memory-in-r"
[17] "/questions/72681898/randomly-delete-columns-from-datasets"
[18] "/questions/72663516/are-rds-files-more-efficient-than-csv-files"
[19] "/questions/72625690/importing-files-using-list-files"
[20] "/questions/72623856/second-most-common-element-in-each-row"
[21] "/questions/72623744/counting-the-position-where-a-pattern-is-completed"
[22] "/questions/72620501/bulk-import-export-files-from-r"
[23] "/questions/72613413/counting-every-position-where-a-pattern-appears"
[24] "/questions/72612577/counting-the-position-of-the-first-0-in-each-row"
[25] "/questions/72607160/taking-averages-across-lists"
[26] "/questions/72589276/functions-for-finding-out-the-midpoint-interpolation"
[27] "/questions/72587298/sandwiching-values-between-rows"
[28] "/questions/72569338/integration-error-lengthlower-1-is-not-true"
[29] "/questions/72568817/synchronizing-nas-in-r"
[30] "/questions/72568661/finding-the-loser-in-each-row"
[[2]]
[1] "/questions/72566170/making-a-race-between-two-variables"
[2] "/questions/72418723/making-a-list-of-random-numbers"
[3] "/questions/72418364/random-uniform-numbers-without-runif"
[4] "/questions/72353102/integrate-normal-distribution-between-2-values"
[5] "/questions/72174868/placing-commas-between-names"
[6] "/questions/72163297/simulate-flipping-french-fries-in-r"
[7] "/questions/71982286/alternatives-to-the-partition-by-statement-in-sql"
[8] "/questions/71970960/converting-lists-into-data-frames"
[9] "/questions/71970672/random-numbers-are-too-similar-to-each-other"
[10] "/questions/71933753/making-combinations-of-items"
[11] "/questions/71874791/sorting-rows-in-specified-order"
[12] "/questions/71866097/hiding-the-legend-in-this-graph"
[13] "/questions/71866048/understanding-the-median-in-this-graph"
[14] "/questions/71852517/nas-produced-when-number-of-iterations-increase"
[15] "/questions/71791906/assigning-unique-colors-to-multiple-lines-on-a-graph"
[16] "/questions/71787336/finding-identical-rows-in-multiple-datasets"
[17] "/questions/71758983/multiple-replace-lookups"
[18] "/questions/71758648/create-ascending-id-in-a-data-frame"
[19] "/questions/71731208/webscraping-data-which-pokemon-can-learn-which-attacks"
[20] "/questions/71728273/webscraping-pokemon-data"
[21] "/questions/71683045/identifying-smallest-element-in-each-row-of-a-matrix"
[22] "/questions/71671488/connecting-all-nodes-together-on-a-graph"
[23] "/questions/71641774/overriding-colors-in-ggplot2"
[24] "/questions/71641404/applying-a-function-to-a-data-frame-lapply-vs-traditional-way"
[25] "/questions/71624111/sending-emails-from-r"
[26] "/questions/71623019/sql-joining-tables-from-2-different-servers-r-vs-sas"
[27] "/questions/71429265/overriding-sql-errors-during-r-uploads"
[28] "/questions/71429129/splitting-a-dataset-into-uneven-portions"
[29] "/questions/71418533/multiplying-and-adding-values-across-rows"
[30] "/questions/71417489/tricking-an-sql-server-to-accept-a-file-from-r"
[[3]]
[1] "/questions/71417218/splitting-a-dataset-into-arbitrary-sections"
[2] "/questions/71398804/plotting-vector-fields-and-gradient-fields"
[3] "/questions/71387596/animating-the-mandelbrot-set"
[4] "/questions/71358405/repeat-a-set-of-ids-for-every-n-rows"
[5] "/questions/71344822/time-series-graphs-with-different-symbols"
[6] "/questions/71341865/creating-a-data-frame-with-commas"
[7] "/questions/71287944/converting-igraph-to-visnetwork"
[8] "/questions/71282863/fixing-the-first-and-last-numbers-in-a-random-list"
[9] "/questions/71282403/adding-labels-to-graph-nodes"
[10] "/questions/71262761/understanding-list-and-do-call-commands"
[11] "/questions/71261431/adjusting-graph-layouts"
[12] "/questions/71255038/overriding-non-existent-components-in-a-loop"
[13] "/questions/71244872/fixing-cluttered-titles-on-graphs"
[14] "/questions/71243676/directly-adding-titles-and-labels-to-visnetwork"
[15] "/questions/71232353/removing-all-edges-in-igraph"
[16] "/questions/71230273/writing-a-function-that-references-elements-in-a-matrix"
[17] "/questions/71227260/generating-random-graphs-according-to-some-conditions"
[18] "/questions/71087349/adding-combinations-of-numbers-in-a-matrix"

how can i select only the links when i bring up the entire class to R?

library:
library(rvest)
library(dplyr)
library(stringr)
library(purrr)
when i use this code i bring up the entire class of the html for site:
links_avai <- paste0("https://avai.com.br/page", seq(from = 1, to = 2)) %>%
map(. %>%
read_html() %>%
html_nodes(xpath = '//*[#class="gdlr-blog-title"]')
runnig it i have te follow result:
[[1]]
{xml_nodeset (8)}
[1] <h3 class="gdlr-blog-title"><a href="https://www.avai.com.br/novo/entenda-como-funciona-o-processo-de-apresentacao-d ...
[2] <h3 class="gdlr-blog-title"><a href="https://www.avai.com.br/novo/ingressos-a-venda-para-avai-x-barra-3a-rodada-do-c ...
[3] <h3 class="gdlr-blog-title"><a href="https://www.avai.com.br/novo/dona-nesi-furlani-recebe-homenagem-do-avai/">Dona ...
[4] <h3 class="gdlr-blog-title"><a href="https://www.avai.com.br/novo/avai-e-superado-pela-chapecoense-na-ressacada/">Av ...
[5] <h3 class="gdlr-blog-title"><a href="https://www.avai.com.br/novo/edital-de-convocacao-reuniao-extraordinaria-do-con ...
[6] <h3 class="gdlr-blog-title"><a href="https://www.avai.com.br/novo/catarinense-2022-confira-o-guia-da-partida-avai-x- ...
[7] <h3 class="gdlr-blog-title"><a href="https://www.avai.com.br/novo/avai-finaliza-preparacao-para-enfrentar-a-chapecoe ...
[8] <h3 class="gdlr-blog-title"><a href="https://www.avai.com.br/novo/catarinense-2022-arbitragem-para-avai-x-chapecoens ..
whit that in mind how can improve my code to selecet only the link from the class?
i alredy tried that code below, but it did not work
links_avai <- paste0("https://avai.com.br/page", seq(from = 1, to = 2)) %>%
map(. %>%
read_html() %>%
html_nodes(xpath = '//*[#class="gdlr-blog-title"]') %>%
html_element("href")
the result was:
{xml_nodeset (8)}
[1] <NA>
[2] <NA>
[3] <NA>
[4] <NA>
[5] <NA>
[6] <NA>
[7] <NA>
[8] <NA>
To get the links use html_attrs, the links are attached to node/element a.
url<-"https://www.avai.com.br/novo/"
url %>%
read_html() %>%
html_nodes('.gdlr-blog-title') %>% html_nodes('a') %>%
html_attr('href')
[1] "https://www.avai.com.br/novo/se-e-baya-e-bom-atacante-paulo-baya-e-apresentado-no-leao/"
[2] "https://www.avai.com.br/novo/comunicado-arquivada-denuncia-no-stjd/"
[3] "https://www.avai.com.br/novo/sob-chuva-leao-se-reapresenta-nesta-tarde-de-quinta-feira/"
[4] "https://www.avai.com.br/novo/entenda-como-funciona-o-processo-de-apresentacao-de-atletas/"
[5] "https://www.avai.com.br/novo/ingressos-a-venda-para-avai-x-barra-3a-rodada-do-catarinense-fort-2022/"
[6] "https://www.avai.com.br/novo/dona-nesi-furlani-recebe-homenagem-do-avai/"
[7] "https://www.avai.com.br/novo/avai-e-superado-pela-chapecoense-na-ressacada/"
[8] "https://www.avai.com.br/novo/edital-de-convocacao-reuniao-extraordinaria-do-conselho-deliberativo-11/"

Get nodes from a html webpage to crawl URLs using R

https://i.stack.imgur.com/xeczg.png
I am trying to get the URLs under the node '.2lines' from the webpage 'https://www.sgcarmart.com/main/index.php'
library(rvest)
url <- read_html('https://www.sgcarmart.com/main/index.php') %>% html_nodes('.2lines') %>% html_attr()
Which I receive an error for html_nodes function:
Error in parse_simple_selector(stream) :
Expected selector, got <NUMBER '.2' at 1>
How do I get around this error?
You can use an xpath selector to find the nodes you want. The links are actually contained in <a> tags within the <p> tags you are trying to reference by class. You can access them in a single xpath:
library(rvest)
site <- 'https://www.sgcarmart.com'
urls <- site %>%
paste0("/main/index.php") %>%
read_html() %>%
html_nodes(xpath = "//*[#class = '2lines']/a") %>%
html_attr("href") %>%
{paste0(site, .)}
urls
#> [1] "https://www.sgcarmart.com/new_cars/newcars_overview.php?CarCode=12485"
#> [2] "https://www.sgcarmart.com/new_cars/newcars_overview.php?CarCode=11875"
#> [3] "https://www.sgcarmart.com/new_cars/newcars_overview.php?CarCode=11531"
#> [4] "https://www.sgcarmart.com/new_cars/newcars_overview.php?CarCode=11579"
#> [5] "https://www.sgcarmart.com/new_cars/newcars_overview.php?CarCode=12635"
#> [6] "https://www.sgcarmart.com/new_cars/newcars_overview.php?CarCode=12507"
#> [7] "https://www.sgcarmart.com/new_cars/newcars_overview.php?CarCode=12644"
#> [8] "https://www.sgcarmart.com/new_cars/newcars_overview.php?CarCode=12622"
#> [9] "https://www.sgcarmart.com/new_cars/newcars_overview.php?CarCode=12650"
#> [10] "https://www.sgcarmart.com/new_cars/newcars_overview.php?CarCode=12651"
#> [11] "https://www.sgcarmart.com/new_cars/newcars_overview.php?CarCode=12589"
#> [12] "https://www.sgcarmart.com/new_cars/newcars_overview.php?CarCode=12649"

How To Extract Name in this HTML Element using rvest

I've searched through many rvest scraping posts but can't find an example like mine. I'm following the R vignette example (https://blog.rstudio.com/2014/11/24/rvest-easy-web-scraping-with-r/) for selectorgadget, but inputting my use case as necessary. None of selector gadget's suggestions get me what I need. I need to extract the name for each review on the page. A sample of what the name looks like under the hood is as follows:
<span itemprop="name" class="sg_selected">This Name</span>
Here's my code to this point. Ideally, this code should get me the individual names on this web page.
library(rvest)
library(dplyr)
dsa_reviews <-
read_html("https://www.directsalesaid.com/companies/traveling-
vineyard#reviews")
review_names <- html_nodes(dsa_reviews,'#reviews span')
df <- bind_rows(lapply(xml_attrs(review_names), function(x)
data.frame(as.list(x), stringsAsFactors=FALSE)))
Apologies if this is a duplicate question or if it's not formatted correctly. Please feel free to request any necessary edits.
Here it is :
library(rvest)
library(dplyr)
dsa_reviews <-
read_html("https://www.directsalesaid.com/companies/traveling-vineyard#reviews")
html_nodes(dsa_reviews,'[itemprop=name]') %>%
html_text()
[1] "Traveling Vineyard" ""
[3] "Kiersten Ray-kuhn" "Miley Sama"
[5] " Nancy Shawtone " "Amanda Moore"
[7] "Matt" "Kathy Barzal"
[9] "Lesa Brinker" "Lori Stryker"
[11] "Jeanette Holtman" "Penny Notarnicola"
[13] "Laura Ann" "Nicole Lafave"
[15] "Gretchen Hess Miller" "Gina Devine"
[17] "Ashley Lawton Converse" "Morgan Williams"
[19] "Angela Baston Mckeone" "Traci Feshler"
[21] "Kisha Marshall Dlugos" "Jody Cole Dvorak"
Colin

html_attr doesn't the 'href' attr

First of all I'm really beginner with web-scraping.
So work on this wesite. I try to get the links to the next webpages with discussion about the espisode. With the SelectorGadget I managed to get only the part of the html with the frame with the topics
html.s1e01 <- html("http://asoiaf.westeros.org/index.php/forum/41-e01-winter-is-coming/")
html.s1e01.page <- html_nodes(html.s1e01, ".ipsBox")
Now I want to get all links to the topics, so I tried
html_attr(html.s1e01.page, "href")
but I get NA. I saw similar examples on the Internet and it should work. Any suggestion why it does not?
html.s1e01.page <- html_nodes(html.s1e01, ".ipsBox .topic_title")
html.s1e01.topics <- html.s1e01.page %>% html_attr("href")
html.s1e01.topics
## [1] "http://asoiaf.westeros.org/index.php/topic/49408-poll-how-would-you-rate-episode-101/"
## [2] "http://asoiaf.westeros.org/index.php/topic/109202-death-of-john-aryn-season-4-episode-5-spoilers/"
## [3] "http://asoiaf.westeros.org/index.php/topic/49310-book-spoilers-episode-101-take-3/"
## [4] "http://asoiaf.westeros.org/index.php/topic/90902-sir-john-standingjonarryn/"
## [5] "http://asoiaf.westeros.org/index.php/topic/106105-did-anyone-notice-the-color-of-the-feather-in-lyannas-tomb/"
## [6] "http://asoiaf.westeros.org/index.php/topic/49116-book-tv-spoilers-what-was-left-out-and-what-was-left-in/"
## [7] "http://asoiaf.westeros.org/index.php/topic/49070-no-spoilers-ep101-discussion/"
## [8] "http://asoiaf.westeros.org/index.php/topic/49159-book-spoilers-the-book-was-better/"
## [9] "http://asoiaf.westeros.org/index.php/topic/57614-runes-in-agot-spoilers-i-suppose/"
## [10] "http://asoiaf.westeros.org/index.php/topic/49151-book-spoilers-ep101-discussion-mark-ii/"
## [11] "http://asoiaf.westeros.org/index.php/topic/49161-booktv-spoilers-dany-drogo/"
## [12] "http://asoiaf.westeros.org/index.php/topic/49071-book-spoilers-ep101-discussion/"
## [13] "http://asoiaf.westeros.org/index.php/topic/49100-no-spoilers-pre-airing-discussion/"