（Python）在.txt中搜索精确的字符串并返回结果

我试图编写一个Python程序，提示用户输入一个字符串，然后打开一个文本文件，搜索文件中的精确匹配项，然后返回与该字符串相关的详细信息

返回的字符串存储到变量中，然后写入一个单独的新.txt文件。（我基本上是在创建一个日志文件，记录我所有的业余无线电联系人）

我遇到的问题是，它返回字符串中的所有内容，而不仅仅是精确匹配。（例如，如果用户输入K8YP，它将返回K8YPA、K8YPB、K8YPC等，而不仅仅是K8YP）

以下是文本文件的结构示例：

EN|215000|||AA0A|L|L00209566|MC CARTHY, DENNIS J|DENNIS|J|MC CARTHY|||||5022 LANSDOWNE AVE|SAINT LOUIS|MO|63109|||000|0002274249|I|||^M
EN|215001|||AA0AA|L|L00196154|MONKS, WILLIAM S|WILLIAM|S|MONKS|||||W 529 Nebraska Hall, UN-L|Lincoln|NE|685880514||c/o Scott L. Gardner, HWML|000|0002268431|I|||^M
EN|215002|||AA0AB|L|L00185374|CROM SR, RAYMOND L|RAYMOND|L|CROM|SR||||12291 BRIGHTON RD|HENDERSON|CO|80640|33||000|0002144756|I|||^M
EN|215003|||AA0AC|L||PETH, ESTHER T|ESTHER|T|PETH|||||BENEDICTINE CONVENT|CLYDE|MO|64432|||000||I|||^M
EN|215004|||AA0AD|L|L00310459|Odermann, William|William||Odermann|||||804 Second Street NW|New Prague|MN|56071|||000|0004694238|I|||^M

我的当前代码列在下面

#This program will log amateur radio contacts and store them in a database.

import time
import sys

def main():
    countdown =3
    print ("\n")
    print "Starting in"

    for countdown in range (3, 0, -1):
        print countdown
        time.sleep(0.25)
    print ("\n")    
    #Asking user for callsign input data
    callsign = raw_input('Please enter the callsign: ')
    print ("\n")

    #Asking user for frequency input data
    frequency = raw_input('Please enter the frequency in MHz: ')
    print ("\n")

    #Asking user to review and confirm the entry
    print ('Callsign: ' + callsign)
    print('Frequency: ' + frequency)
    print ("\n")

    request = raw_input('Enter 1 to confirm and 0 to cancel: ')
    print ("\n")

    #Commands for grabbing date and time
    date_time_stamp = time.strftime("%c")

    if request == '1':
        with open('EN.dat', 'r') as searchfile:
            for line in searchfile:
                if callsign in line:
                    text_file = open("Contact_Logs.txt", "a")
                    text_file.write("Callsign: %s\n" % callsign)
                    text_file.write("Frequency: %s\n" % frequency)
                    text_file.write("Date/Time: %s\n" % date_time_stamp)
                    text_file.write("%s\n" % line)
                    text_file.close
                    print line
                    print("The contact was logged successfully!")
                    print ("\n")

    else:
        print "Log request was cancelled!"
        print ("\n")

    return 0

if __name__ == '__main__':
    main()

非常感谢任何帮助解决我的问题。：）

谢谢，

---

Andrew

根据提供的示例，您应该搜索

“|”+callsign+“|”

以避免误报：

如果（“|”+callsign+“|”）在第行：

。这假定“|”和呼号等之间不能有空格

基于正则表达式的方法将更加健壮，但需要做更多的工作