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How to print strings from a text file,separated by new line in Python

I'm new in Python and i'm challenging myself by making an online library management with prompt for the 1st phase.I'm stacked in search function.I have found how to print a user's input,but i can't find how to print and the following data.I want to search a book by name.If book's name is in the text,i want to print the details of the book,like author,isbn etc.
Here is the following code i have made:
def search():
search_book = input('Search a book: ')
with open('library.txt', mode='r', encoding='utf-8') as f:
index = 0
for line in f:
index += 1
if search_book in line:
print(f'{search_book} is in line {index}')
for details in range(index,index+5):
print(line[details])
And this is the text file's data:
FIRST
ME
9781234
2000
Science
SECOND
YOU
9791234
1980
Literature
It is separated by new line.As example a user input the name FIRST and the result will be:
FIRST
ME
9781234
2000
Science

There are two file options we can consider,
Csv file - Instead of individual readline, you could use one line for one book entry.
# ---------test.csv -------------
# BookName, ItemCode, Price
# Book1, 00012, 14.55
# Book2, 00232, 55.12
# -----End Csv-------------------
import csv
def read_csv(filename:str):
file_contents = None
# reading csv file
with open(filename, 'r') as csvfile:
file_contents = csv.reader(csvfile)
return file_contents
def search(file_contents, book_name:str):
if not file_contents:
return None
for line in file_contents:
if book_name in line:
return line
if __name__ == '__main__':
file_contents = read_csv('test.csv')
line = search(file_contents, 'ME')
print(line if line else 'No Hit Found')
Json - This is much better option than csv file
import json
def read_json(filename:str) -> dict:
with open(filename) as json_file:
all_books = json.load(json_file)
return all_books
def search(all_books:dict, book_name:str):
for book_id, book_details in all_books.items():
if book_details['Name'] == book_name:
return book_details
return None
if __name__ == '__main__':
all_books = read_json('books.json')
book = search(all_books, 'YOU')
print(book if book else 'Not hit found')
If your file contents can't change, then I will go with #tripleee suggestion above. Good luck.

You are reading a line at a time, and looping over the first line's contents. At this point in the program, there are not yet any additional lines. But a fix is relatively easy:
def search():
search_book = input('Search a book: ')
with open('library.txt', mode='r', encoding='utf-8') as f:
index = 0
print_this_many = 0
for line in f:
index += 1
if search_book in line:
print(f'{search_book} is in line {index}')
print_this_many = 5
if print_this_many:
print(line, end='')
print_this_many -= 1
We don't have the next lines in memory yet, but we can remember how many of them to print as we go ahead and read more of them. The print_this_many variable is used for this: When we see the title we want, we set it to 5 (to specify that this and the next four lines should be printed). Now, each time we read a new line, we check if this variable is positive; if it is, we print the line and decrement the variable. When it reaches zero, we will no longer print the following lines. This allows us to "remember" across iterations of the for loop which reads each new line whether we are in the middle of printing something.
A much better solution is to read the database into memory once, and organize the lines into a dictionary, for example.
def read_lib(filename):
library = dict()
with open(filename) as lib:
title = None
info = []
for line in lib:
line = line.rstrip('\n')
if title is None:
title = line
elif line == '':
if title and info:
library[title] = info
title = None
else:
info.append(line)
def search(title, library):
if title in library:
return library[title]
else:
return None
def main():
my_library = read_lib('library.txt')
while True:
sought = input('Search a book: ')
found = search(sought, my_library)
if found:
print('\n'.join(found))
else:
print('Sorry, no such title in library')

How do I get rid of a random new line in the middle of a line in a text file using Python?

The following code will take the contents of 'out.txt' and append it to the end of 'fixed_inv.txt' in the form of a new file, 'concat.txt' based on
a shared path.
In the 'concat.txt' file, I am getting a few rows (out of thousands) that seem to have a random new line in the middle of said line.
For instance, a line is supposed to look like:
122 abc.def.com Failed to get CIFS shares with error code -2147024891. None Non-supported share access type. 0 Unkonwn NULL bluearc Different Security Type (1), Access is denied. (1354), Pruned. Different security type (21), The inherited access control list (ACL) or access control entry (ACE) could not be built. (3713), Could not convert the name of inner file or directory (27)
But instead, I have a few looking like:
122 abc.def.com Failed to get CIFS shares with error code -2147024891. None
Non-supported share access type. 0 Unkonwn NULL bluearc Different Security Type (1), Access is denied. (1354), Pruned. Different security type (21), The inherited access control list (ACL) or access control entry (ACE) could not be built. (3713), Could not convert the name of inner file or directory (27)
I have tried to fix this in my code below, but for some reason the code runs but does not fix the issue - which is to backspace the misplaced half line back or to get rid of the random new line.
class Error:
def __init__ (self, path, message): #self = new instance of class
self.path = path
self.message = message #error message
self.matched = False #has the path from out.txt been matched to the path of fixed_inv.txt?
def open_files(file1, file2, file3):
try:
f1 = open(file1, 'r')
except IOError:
print("Can't open {}".format(file1))
return None, None, None #you can't just open one file you have to open all
else:
try:
f2 = open(file2, 'r')
except IOError:
print("Can't open {}".format(file2))
f1.close()
return None, None, None
else:
try:
f3 = open(file3, 'w')
except IOError:
print("Can't open {}".format(file3))
f1.close()
f2.close()
return None, None, None
else:
return f1, f2, f3
def concat(file1, file2, file3):
errors = {} #key: path, value: instance of class Error
f1, f2, f3 = open_files(file1, file2, file3)
prevLine = "" #NEW
if f1 is not None: #if file one is able to open...
with f1:
for line_num, line in enumerate(f1): #get the line number and line
line = line.replace("\\", "/") #account for the differences in backslashes
tokens = line.strip().split(': ') #strip white spaces, split based on ':'
if len(tokens) != 3: #if there's less than two tokens...
print('Error on line {} in file {}: Expected three tokens, but found {}'.format(line_num + 1, file1, len(tokens))) #error
else: #NEW
if line.startswith('Non-supported'): #NEW
Prevline = line
Prevline = line.strip('\n') #NEW
else:
errors[tokens[1]] = Error(tokens[1], tokens[2])
with f2:
with f3:
for line_num, line in enumerate(f2):
line = line.replace("\\", "/").strip() #account for the differences in backslashes
tokens_2 = line.strip().split('\t') #strip white spaces, split based on tab
if len(tokens_2) < 4: #if we are unable to obtain the path by now since the path should be on 3rd or 4th index
print('Error on line {} in file {}: Expected >= 4 tokens, but found {}'.format(line_num + 1, file2, len(tokens_2)))
f3.write('{}\n'.format(line))
else: #if we have enough tokens to find the path...
if tokens_2[3] in errors: #if path is found in our errors dictionary from out.txt...
line.strip('\n')
path = tokens_2[3] #set path to path found
msg = errors[path].message #set the class instance of the value to msg
errors[path].matched = True #paths have been matched
f3.write('{}\t{}\n'.format(line, msg)) #write the line and the error message to concat
else: #if path is NOT found in our errors dictionary from out.txt...
f3.write('{}\t{}\n'.format(line, 'None'))
print('Error on line {} in file {}: Path {} not matched'.format(line_num + 1, file2, tokens_2[3])) #found in fixed_inv.txt,
#but not out.txt
"""for e in errors: #go through errors
if errors[e].matched is False: #if no paths have been matched
print('Path {} from {} not matched in {}'.format(errors[e].path, file1, file2)) #found in out.txt, but not in fixed_inv
f3.write('{}\t{}\n'.format(line, 'No error present'))
def main():
file1 = 'out.txt'
file2 = 'fixed_inv.txt'
file3 = 'test_concat.txt'
concat(file1, file2, file3)
if __name__ == '__main__':
main()
Any ideas/advice would be greatly appreciated! Thank you.

try replacing newline chars before writing it.
Ex:
f3.write('{}\n'.format(line.strip().replace("\n", "")))
f3.write('{}\t{}\n'.format(line.strip().replace("\n", ""), msg.replace("\n", "")))
f3.write('{}\t{}\n'.format(line.strip().replace("\n", ""), 'None'))

If you can fix this on the output side, it will obviously be a lot easier and more robust. But if you can’t, what you’re doing is a start in the right direction. You just want to:
Use prevline + line in place of line the first time.
Set prevline = “” in successful cases.
Do the check for an incomplete line before reading an error instead of after.
Distinguish too few tokens (may be an incomplete line) from too many (definitely an error) instead of trying to treat them the same.
Possibly (depending on actual input) replace new lines with some other white space instead of nothing.
Also, you may want to wrap this logic up in a generator function that you can reuse. Something like this:
def tokenizing(lines):
prevline = ""
for line in lines:
line = prevline + line
line = line.strip_logic_goes_here()
tokens = tokenize_logic_goes_here(line)
if len(tokens) > REQUIRED_TOKENS:
raise AppropriateException()
elif len(tokens) == REQUIRED_TOKENS:
yield line, tokens
prevline = ""
else:
prevline = line
if not prevline: return
tokens = tokenize_logic_goes_here()
if len(tokens) != REQUIRED_TOKENS:
raise AppropriateException()
yield line, tokens
Then you can just write;
for line, tokens in tokenizing(f1):

Search file for input Python

I am writing a program to read a text file of zip codes that should print the location of the zip code when the correct number is input. However, I am having trouble writing the error message. I have tried various methods and cannot get the error message to print, here is what I have:
try:
myFile=open("zipcodes.txt") #Tries to open file user entered
except:
print "File can't be opened:", myFile #If input is invalid filename, print error
exit()
zipcode = dict() #List to store individual sentences
line = myFile.readline() #Read each line of entered file
ask = raw_input("Enter a zip code: ")
if ask not in line:
print "Not Found."
else:
for line in myFile:
words = line.split()
if words[2] == ask:
zipcode = words[0:2]
for value in zipcode:
print value,
Some sample ZIP codes:
Abbeville AL 36310
Abernant AL 35440
Acmar AL 35004
Adamsville AL 35005
Addison AL 35540
Adger AL 35006
Akron AL 35441
Alabaster AL 35007

I'm not sure of the significance of enterFile. You should see the error message if you remove enterFile from the exception because it doesn't appear to be defined.

From the beginning:
try:
myFile=open("zipcodes.txt")
except:
print "File can't be opened:", myFile # if open fail then myFile will be undefined.
exit()
zipcode = dict() # you creating dict, but you never add something into it.
line = myFile.readline() # this will read only first line of file, not each
ask = raw_input("Enter a zip code: ")
if ask not in line:
# it will print not found for any zipcode except zipcode in first line
print "Not Found."
else:
# because you already read 1 line of myFile
# "for line in " will go from second line to end of file
for line in myFile: # 1 line already readed. Continue reading from second
words = line.split()
if words[2] == ask: # If you don't have duplicate of first line this will never be True
zipcode = words[0:2]
# So here zipcode is an empty dict. Because even if "ask is in line"
# You never find it because you don't check line
# where the ask is (the first line of file).
for value in zipcode:
# print never executed becouse zipcode is empty
print value,

I believe that you need two phases in this program:
Read zipcodes.txt and build your directory.
Ask the user for a ZIP code; print the corresponding location.
Your current "positive" logic is
else:
for line in myFile:
words = line.split() # Get the next line from zipcodes.txt
if words[2] == ask: # If this ZIP code matches the input,
zipcode = words[0:2] # assign the line's three fields as a list.
# Variable zipcode now contains a single line's data, all three fields.
# You threw away the empty dictionary.
for value in zipcode: # Print all three fields of the one matching line.
print value,
Needed Logic (in my opinion)
# Part 1: read in the ZIP code file
# For each line of the file:
# Split the line into location and ZIP_code
# zipcode[ZIP_code] = location
# Part 2: match a location to the user's given ZIP code
# Input the user's ZIP code, "ask"
# print zipcode[ask]
Does this pseduo-code get you moving toward a solution?

Reading file from the internet and split into 2

I am brand new to Python and try the following: I am reading a file from the internet and want to split it at a certain amount of lines.
1. File = line 1 to x
2. File = line x+1 to eof
I use httplib2 to read the file from the internet and split then this file into 2. Tried it with the "with" but it seems that I cannot use f.readline() etc when I am reading a file from the internet and use it with "with". If I open a local file it works fine.
Do I miss something here?
Thank you very much for your help in advance.
with data_file as f: #data_file is the file read from the internet
Here is my function:
def create_data_files(data_file):
# read the file from the internet and split it into two files
# Loading file give info if the file was loaded from cache or internet
try:
print("Reading file from the Internet or Cache")
h = httplib2.Http(".cache")
data_header, data_file = h.request(DATA_URL) # , headers={'cache-control':'no-cache'}) # to force download form internet
data_file = data_file.decode()
except httplib2.HttpLib2Error as e:
print(e)
# Give the info if the file was read from the internet or from the cache
print("DataHeader", data_header.fromcache)
if data_header.fromcache == True:
print("File was read from cache")
else:
print("File was read from the internet")
# Counting the amount of total characters in the file - only for testing
# print("Total amount of characters in the original file", len(data_file)) # just for testing
# Counting the lines in the file
print("Counting lines in the file")
single_line = data_file.split("\n")
for value in single_line:
value =value.strip()
#print(value) # juist for testing - prints all the lines separeted
print("Total amount of lines in the original file", len(single_line))
# Asking the user how many lines in percentage of the total amount should be training data
while True:
#split_factor = int(input("What percentage should be use as training data? Enter a number between 0 and 100: "))
split_factor = 70
print("Split Factor set to 70% for test purposes")
if 0 <= split_factor <= 100:
break
print('try again')
split_number = int(len(single_line)*split_factor/100)
print("Number of Training set data", split_number) # just for testing
# Splitting the file into 2
training_data_file = 0
test_data_file = 0
return training_data_file, test_data_file

from collections import deque
import httplib2
def create_data_files(data_url, split_factor=0.7):
h = httplib2.Http()
resp_headers, content = h.request(data_url, "GET")
# for python3
content = content.decode()
lines = deque(content.split('\n'))
stop = len(lines) * split_factor
training, test = [], []
i = 0
while lines:
l = lines.popleft()
if i <= stop:
training.append(l)
else:
test.append(l)
i +=1
training_str, test_str = '\n'.join(training), '\n'.join(test)
return training_str, test_str
This should do the trick (not tested and simplified).
data_header, data_file = h.request(DATA_URL)
data_file is not a file like object but a string

UnpicklingError: Invalid load key'(heart)'

I've been messing around with pickle for some days, trying to apply it in a High Score system in a 'Guess the number' exercise program. I thought that I had grasped the concept correctly, but now this error has appeared and I have no clue as to why.
Here's the relevant code:
def EnterHighScore(score,scoresList):
name = input("Enter your name: ")
newPlayer = player(name,score)
scoresList.append(newPlayer)
scoresFile = open('scores','wb')
pickle.dump(scoresList,scoresFile)
scoresFile.close()
for i in scoresList:
print(i.name + ' - ' + str(i.score))
def CheckHighScores(score):
try:
scoresFile = open('scores','rb')
except:
scoresFile = open('scores','wb+')
if not scoresFile.read(1):
scoresList = []
else:
scoresList = pickle.load(scoresFile)
scoresFile.close()
if not scoresList:
EnterHighScore(score,scoresList)
else:
for counter,i in enumerate(scoresList):
if counter == 3:
break
if score >= i.score:
EnterHighScore(score,scoresList)
break
When I run it, the first run through goes fine. That is, when the 'scores' file doesn't even exist. It gets created correctly, the scoresList is created empty and then filled with a player object and it gets dumped into the scoresFile without any errors. But when I try to load the scoresList with the new 'scores' file data, it gives me the following error:
UnpicklingError: Invalid load key'(heart)'
(heart) standing for an actual heart character.
I've read that others have had this problem, but in those cases they were trying to open the file in different OS's, or had modified the file in some way after pickling but before unpickling. In this case the file hasn't been modified at all, just written to and closed.
I've tried using pickle in other, simpler scenarios, and I haven't caused other errors.
Any help will be appreciated.

Your test to see if the file is empty advances the file read pointer past the start of the file:
if not scoresFile.read(1):
You'll have to seek back to the beginning:
if not scoresFile.read(1):
scoresList = []
else:
scoresFile.seek(0)
scoresList = pickle.load(scoresFile)
A much better test would be for you to catch the EOFError exception that pickle.load() throws if the file is empty:
try:
scoresList = pickle.load(scoresFile)
except EOFError:
# File empty
scoresList = []
Or you could catch the IOError when the file doesn't exist:
try:
with open('scores','rb') as scoresFile:
scoresList = pickle.load(scoresFile)
except IOError:
scoresList = []
and just not open a file for writing here.