Question

我想从数据帧from selenium import webdriver from selenium.webdriver.common.by import By from selenium.webdriver.support.ui import WebDriverWait from selenium.webdriver.support import expected_conditions as EC from selenium.common.exceptions import TimeoutException import time link = "https://in.finance.yahoo.com/quote/AAPL?p=AAPL" def get_information(driver, url): driver.get(url) driver.find_element_by_tag_name("body").send_keys(Keys.END) # scroll page time.sleep(1) # small pause between driver.find_element_by_tag_name("body").send_keys(Keys.END) # one more time item = wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, "[id$='-QuoteModule'] p[class^='businessSummary']"))) driver.execute_script("arguments[0].scrollIntoView();", item) print(item.text) if __name__ == "__main__": driver = webdriver.Chrome() wait = WebDriverWait(driver, 20) try: get_information(driver,link) finally: driver.quit()中抽取许多连续的行。

df

我正在尝试获取类似于以下内容的内容，该内容使我可以对3个随机行进行采样并重复此过程100次。

df <- data.frame(C1 = c(1, 2, 4, 7, 9), C2 = c(2, 4, 6, 8, 10))

通过连续，结果应类似于：

test <- replicate(100, df[sample(1:nrow(df), 3, replace=T),], simplify=F)

我该如何实现？

Answer 1

我们只需要采样一个块的起始行索引即可。

sample.block <- function (DF, chunk.size) {
  if (chunk.size > nrow(DF)) return(NULL)
  start <- sample.int(nrow(DF) - chunk.size + 1, 1)
  DF[start:(start + chunk.size - 1), ]
  }

replicate(100, sample.block(df, 3), simplify = FALSE)

从数据帧或矩阵中随机采样连续的行

1 个答案: