在 R 中使用正则表达式从 PDF 中提取特定单词

Question

Click here to see the PDF file

我正在尝试从上面的 PDF 文件中提取 Start、Finish、Job Number Description 和 Tutor。

下面的代码给出了 Start、Finish 和 Job Number，但我还需要提取相应 Job numbers 的其余文本。

a<-str_match_all(extracted_pdf, "(\d{1,2}/\d{1,2}/\d{4})\W+(\d{1,2}/\d{1,2}/\d{4})\W+(\d+)")

你能帮我看看如何提取这些文本并将其变成 table 吗？

Answer 1

这是我对你的尝试。我在我的代码中提供了解释。处理 PDF 数据并不容易；它需要一些编码。但是一旦找到模式，就可以清理数据。

library(tidyverse)
library(pdftools)
library(splitstackshape)

# Import the PDF, create a data frame, remove unnecessary columns and rows.
# I removed rows that were not included in the table.

foo <- pdf_data(pdf = "Client.pdf", opw = "", upw = "") %>% 
       as.data.frame %>% 
       select(-c(width, height, space)) %>% 
       slice(-(1:(grep(x = text, pattern = "^Start") - 1))) # Remove irrelevant rows.

# Get indices for dates. First, I identified which rows contain /, since / indicates dates.
# Then, I further subset the indices so that I can identify where each row of the
# table begins.

ind <- grep(x = foo$text, pattern = "/")
dummy <- c(diff(ind), NA)
ind <- ind[dummy == 1 & complete.cases(dummy)]

# Create a group variable with findInterval(). Concatenate texts for each group.
# Handle some string manipulation. Split the string and create columns.

group_by(foo, id = findInterval(x = 1:n(), vec = ind)) %>% 
summarize(text = paste0(text, collapse = "_")) %>% 
mutate(text = sub(x = text, pattern = "(Job|Tutor)_(Number|Name)", replacement = "\1 \2"),
       text = gsub(x = text, pattern = "(?<=,|Project)_", replacement = " ", perl = TRUE)) %>% 
cSplit(splitCols = "text", sep = "_", direction = "wide", type.convert = FALSE) -> res

# Set up column names
names(res) <- setNames(nm = c("id", unlist(res[1, ])[-1]))

# Remove the first row since it contains column names.
slice(res, -1) -> res

  id        Start     Finish Job Number                                  Description      Tutor
1  1   29/11/2019 29/11/2019    2288288 Project Name, Project Location, Project Type Tutor Name
2  2    2/12/2019  2/12/2019    8282888 Project Name, Project Location, Project type Tutor Name
3  3    9/12/2019  9/12/2019    2828288 Project Name, Project Location, Project Type Tutor Name
4  4 18/12//2019. 20/12/2019    2828289 Project Name, Project Location, Project Type Tutor Name

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