在Python中从多个文本文件中定位和提取字符串

Question

我刚刚开始学习Python，为了工作，我浏览了很多pdf，所以我找到了一个PDFMINER工具，可以将目录转换成文本文件。然后我做了下面的代码来告诉我这个pdf文件是一个被批准的声明还是一个被拒绝的声明。我不明白我怎么能说找到以“跟踪识别号…”开头的字符串，然后是18个字符，然后把它塞进一个数组？你知道吗

import os
import glob
import csv
def check(filename):
    if 'DELIVERY NOTIFICATION' in open(filename).read():
        isDenied = True
        print ("This claim was Denied")
        print (isDenied)
    elif 'Dear Customer:' in open(filename).read():
        isDenied = False
        print("This claim was Approved")
        print (isDenied)
    else:
        print("I don't know if this is approved or denied")

def iterate():

    path = 'text/'
    for infile in glob.glob(os.path.join(path, '*.txt')):
        print ('current file is:' + infile)
        filename = infile
        check(filename)


iterate()

任何帮助都将不胜感激。这就是文本文件的样子

Shipper Number............................577140Pickup Date....................................06/27/17
Number of Parcels........................1Weight.............................................1 LBS
Shipper Invoice Number..............30057010Tracking Identification Number...1Z000000YW00000000
Merchandise..................................1 S NIKE EQUALS EVERYWHERE T BK B
WE HAVE BEEN UNABLE TO PROVIDE SATISFACTORY PROOF OF DELIVERY FOR THE ABOVE
SHIPMENT.  WE APOLOGIZE FOR THE INCONVENIENCE THIS CAUSES.
NPT8AEQ:000A0000LDI 07
----------------Page (1) Break----------------

更新：许多有用的答案，这是我采取的路线，如果我自己这么说的话，效果相当不错。这会节省很多时间！！以下是我的全部代码，供将来的观众使用。你知道吗

import os
import glob

arrayDenied = []

def iterate():
    path = 'text/'
    for infile in glob.glob(os.path.join(path, '*.txt')):
        print ('current file is:' + infile)
        check(infile)

def check(filename):
    with open(filename, 'rt') as file_contents:
        myText = file_contents.read()
        if 'DELIVERY NOTIFICATION' in myText:
            start = myText.index("Tracking Identification Number...") + len("Tracking Identification Number...")
            myNumber = myText[start : start+18]
            print("Denied: " + myNumber)
            arrayDenied.append(myNumber)
        elif 'Dear Customer:' in open(filename).read():
print("This claim was Approved")

startTrackingNum = myText.index("Tracking Identification Number...") + len("Tracking Identification Number...")
myNumber = myText[startTrackingNum : startTrackingNum+18]

startClaimNumberIndex = myText.index("Claim Number ") + len("Claim Number ")
myClaimNumber = myText[startClaimNumberIndex : startClaimNumberIndex+11]

arrayApproved.append(myNumber + " - " + myClaimNumber)
        else:
            print("I don't know if this is approved or denied")   
iterate()
with open('Approved.csv', "w") as output:
    writer = csv.writer(output, lineterminator='\n')
    for val in arrayApproved:
        writer.writerow([val])
with open('Denied.csv', "w") as output:
    writer = csv.writer(output, lineterminator='\n')
    for val in arrayDenied:
        writer.writerow([val])
print(arrayDenied) 
print(arrayApproved)

更新：添加了我完成的代码的其余部分，将列表写入CSV文件，在那里执行some=left（）之类的命令，几分钟内我就有了1000个跟踪号码。这就是为什么编程是伟大的。你知道吗

Answer 1

如果您的目标只是找到“跟踪标识号…”字符串和随后的18个字符；您可以只找到该字符串的索引，然后到达它的结尾，并从该点开始切片，直到随后的18个字符的结尾。你知道吗

# Read the text file into memory:
with open(filename, 'rt') as txt_file:
    myText = txt_file.read()
    if 'DELIVERY NOTIFICATION' in myText:
        # Find the desired string and get the subsequent 18 characters:
        start = myText.index("Tracking Identification Number...") + len("Tracking Identification Number...")
        myNumber = myText[start : start+18]
        arrayDenied.append(myNumber)

您还可以将append行修改为arrayDenied.append(myText + ' ' + myNumber)或类似的内容。你知道吗

Answer 2

我认为这解决了你的问题，只是把它变成一个函数。你知道吗

import re

string = 'Tracking Identification Number...1Z000000YW00000000'

no_dots = re.sub('\.', '', string) #Removes all dots from the string

matchObj = re.search('^Tracking Identification Number(.*)', no_dots) #Matches anything after the "Tracking Identification Number"

try:
   print (matchObj.group(1))
except:
    print("No match!")

如果您想阅读文档，请点击这里：https://docs.python.org/3/library/re.html#re.search

Answer 3

正则表达式是完成任务的方法。下面是一种修改代码以搜索模式的方法。你知道吗

import re
pattern = r"(?<=Tracking Identification Number)(?:(\.+))[A-Z-a-z0-9]{18}"

def check(filename):
    file_contents = open(filename, 'r').read()
    if 'DELIVERY NOTIFICATION' in file_contents:
        isDenied = True
        print ("This claim was Denied")
        print (isDenied)
        matches = re.finditer(pattern, test_str)
        for match in matches:
            print("Tracking Number = %s" % match.group().strip("."))
    elif 'Dear Customer:' in file_contents:
        isDenied = False
        print("This claim was Approved")
        print (isDenied)
    else:
        print("I don't know if this is approved or denied")

解释：

r"(?<=Tracking Identification Number)(?:(\.+))[A-Z-a-z0-9]{18}"

• (?<=Tracking Identification Number)在捕获组后面查找字符串“Tracking Identification Number”
• (?:(\.+))匹配一个或多个点（.）（我们在后面去掉这些点）
• [A-Z-a-z0-9]{18}匹配18个（大写或小写）字母或数字实例

更多关于Regex。你知道吗