元组的字符串参数-python

Question

I have opened a text file and printed it out. I am trying to allow the user to input details(first name or department name 'CSEE') of the line they would like to print in tuple's in this order:

 Timothy, Johnson      12345 Law      £25000

This is the code I have so far.

fob=open('c:/Users/username/Desktop/CE151 Python/ass2/info.txt','r')
print("enter student file name: )")
text_file = open("info.txt","r")
for item in fob:
    for y in item:
        item.split(' ')
        print(item)
        break
find = input('Input Details: ')
for find in item:
    print(find)

the info.txt file contains:

12345 Law 35000 Bob Liam
12346 Biology 25000 Tom Hanks
12350 Economics 30000 Billy Kid
13123 Economics 55000 Finn Balor
13124 Maths 40000 David Young
13126 Physics 25000 John Wayne Smith
13127 History 35000 Tony Gregg
13128 History 27500 Lily Joe
13129 Chemistry 25000 Saxton Crown
13130 Law 22000 jimmy Arrow

I want the user to input information, for example if the user inputs History, then the all the people studying history will be printed

Answer 1

It seems like your task is pretty simple - simply to open a file, and then for each line read some space separated data from it, and rearrange it. This can be done very concisely in Python. I'm not quite sure why you have so many input s, I think you'll need at most one, if you want the user to be able to enter the file name interactively. Here is my code:

#open the file
with open("input.txt") as student_file:
    #for each line
    for line in student_file:
        #read some space separated data and rearrange it
        print("{3}, {4}\t{0}\t{1}\t£{2}".format(*line.split()))

Where input.txt has your input, this leads to the output

Bob, Liam   12345   Law £35000
Tom, Hanks  12346   Biology £25000
Billy, Kid  12350   Economics   £30000
Finn, Balor 13123   Economics   £55000
David, Young    13124   Maths   £40000
John, Wayne 13126   Physics £25000
Tony, Gregg 13127   History £35000
Lily, Joe   13128   History £27500
Saxton, Crown   13129   Chemistry   £25000
jimmy, Arrow    13130   Law £22000

This output has been tab separated, which seemed close to what you wanted. If you want it to be space separated again, you can replace the \\t s with spaces. If you want it to be space separated but still aligned, this might take some more work.

Updating the code to suit your new requirement, I think:

target_course = input("which course should be filtered by? ")
with open("input.txt") as student_file:
    for line in student_file:
        data = line.split()
        if data[1] == target_course:
            print("{3}, {4}\t{0}\t{1}\t£{2}".format(*data))

Example of it in action:

which course should be filtered by? History
Tony, Gregg 13127   History £35000
Lily, Joe   13128   History £27500

If the idea is for them to filter by whatever field they like, this might get a little more complicated. I would use a namedtuple , and check with that. This can be done like below:

from collections import namedtuple

fields = ["forename", "surname", "id", "subject", "cost"]

Row = namedtuple("Row", fields)

target_field = input("what field do you want to filter by (one of {})? ".format(fields))
target_value = input("what value do you want to filter by? ")

with open("input.txt") as student_file:
    for line in student_file:
        id_, subject, cost, forename, *surname = line.split()
        data = Row(id=id_, subject=subject, cost=cost, forename=forename, surname=" ".join(surname))
        if getattr(data, target_field) == target_value:
            print("{0.surname}, {0.forename}\t{0.id}\t{0.subject}\t£{0.cost}".format(data))

Along with this refactoring, the code may have become a little clearer. Note that I've fixed a bug I actually realised it had previously - it couldn't handle multiple word surnames. Embarassing especially as multiple word surnames and the handling thereof are very close to my heart. It now works as follows:

what field do you want to filter by (one of ['forename', 'surname', 'id', 'subject', 'cost'])? subject
what value do you want to filter by? History
Gregg, Tony 13127   History £35000
Joe, Lily   13128   History £27500

what field do you want to filter by (one of ['forename', 'surname', 'id', 'subject', 'cost'])? cost
what value do you want to filter by? 25000
Hanks, Tom  12346   Biology £25000
Wayne Smith, John   13126   Physics £25000
Crown, Saxton   13129   Chemistry   £25000

Note that it's not very sophisticated yet - it doesn't do any input validation, for example, and cost is given as an integer not prefixed by a £. This is something you can try to add to the program.