python - importing and exporting from csv files -

so trying create code can search data file:

1. by surname retrieve , display details contact
2. by date of birth retrieve , display contacts birthday in particular month.

here code have created:

def search():     option = input('please select search \n1. surname\n2. d.o.b\n')     if option == '1':         surname = input('please enter surname: ')         while not surname.isalpha():             surname = str(input('please enter valid surname: '))         myfile = open('address book.csv', 'rt')         line in myfile:             if ',' + str(surname) + ',' in line:                 print(line)             else:                  print('no contacts found')     elif option == '2':         validmonth = false         while validmonth == false:             month = input('please enter birth month')             if month >='13' , month <='0':                 print('please enter valid month')             else:                 validmonth = true             myfile = open ('address book.csv', 'rt')             line in myfile:                 if str(month) in line:                     print(line)                 else:                     print('no contacts found')     else:         print('error, select valid option')         search()  search() 

i keep getting result when try code:

please select search  1. surname 2. d.o.b 1 please enter surname: vickers no contacts found no contacts found no contacts found no contacts found no contacts found no contacts found no contacts found no contacts found 

i want know why? please help?

you test surname on every row, print no contacts found every row doesn't match.

break out of loop when find name, , use else suite for loop instead:

for line in myfile:     if ',' + str(surname) + ',' in line:         print(line)         break else:     print('no contacts found') 

else on for loop executed if exhausted iterable, when did not break out of loop early.

your surnames first value on line, better off testing if line starts surname:

if line.startswith(surname + ','): 

pro tip: when reading csv files, use csv module:

import csv  open('address book.csv', newline='') myfile:     reader = csv.reader(myfile)     row in reader:         if row[0] == surname:             print(row)             break     else:          print('no contacts found')