p18.py

# Read text file

# open function
# read method
# seek method
# tell method
# readline method
# readlines method
# close method

# path=(r'F:\Courses\python hindi\harshit vashisth\file1.txt')

f=open('file1.txt')                   # here i have to put txt file's path if .py file and .txt file are not in same folder.
                                      # f=open('file1.txt','r') ---for read file, f=open('file1.txt','w') ---for write file, f=open('file1.txt')----bydefault is reading mode
print(f.read())                # f.read() will return me the file data in string form
f.close()

# o/p: 
#      -------------- Important things to remember -----------------
#      -- never do something to impress someone.
#      -- never live your life on someone else opinions.
#      -- Just find whatever you love and then hustle untill you don't need to introduce yourself.




f1=open('file1.txt')                      # o/p: -------------- Important things to remember -----------------
print(f1.read())                          #      -- never do something to impress someone.
print(f1.read())                          #      -- never live your life on someone else opinions.
f1.close()                                #      -- Just find whatever you love and then hustle untill you don't need to introduce yourself.
# python will return file data only one time even though we wrote print(f1.read()) two times. 
# this is happen because python read text file according to cursor, hemce when second time print(f1.read()) executed, our cursor was on last position in file, therefore we got data only one time




f2=open('file1.txt')                      # o/p: cursor position - 0
print(f"cursor position - {f2.tell()}")   #      -------------- Important things to remember -----------------
print(f2.read())                          #      -- never do something to impress someone.
print(f"cursor position - {f2.tell()}")   #      -- never live your life on someone else opinions.
print(f2.read())                          #      -- Just find whatever you love and then hustle untill you don't need to introduce yourself.
f2.close()                                #      cursor position - 250

# tell() method is used for getting position of cursor






# seek() method----> it is used for changing the position of cursor
f3=open('file1.txt') 
print(f"cursor position - {f3.tell()}")                    
print(f3.read())   
print(f"cursor position - {f3.tell()}") 
print("Before seek method")
f3.seek(0)     
print("After seek method")
print(f"cursor position - {f3.tell()}")    
print(f3.read())                          
f3.close()                              

# o/p: cursor position - 0
#      -------------- Important things to remember -----------------
#      -- never do something to impress someone.
#      -- never live your life on someone else opinions.
#      -- Just find whatever you love and then hustle untill you don't need to introduce yourself.
#      cursor position - 248
#      Before seek method
#      After seek method
#      cursor position - 0
#      -------------- Important things to remember -----------------
#      -- never do something to impress someone.
#      -- never live your life on someone else opinions.
#      -- Just find whatever you love and then hustle untill you don't need to introduce yourself.






# readline() method  ----> read one line at a time

f4=open('file1.txt')     
print(f4.readline())                          
f4.close()                          # o/p: -------------- Important things to remember -----------------


f4=open('file1.txt')     
print(f4.readline())        
print(f4.readline())                          
print(f4.readline())                          
f4.close()

# o/p: -------------- Important things to remember -----------------

#      -- never do something to impress someone.

#      -- never live your life on someone else opinions.


f4=open('file1.txt')     
print(f4.readline(),end='')         # to remove space between two line
print(f4.readline())                          
print(f4.readline())                          
f4.close()

# o/p: -------------- Important things to remember -----------------
#      -- never do something to impress someone.

#      -- never live your life on someone else opinions.





# readlines() method ----> it will make list of lines which are in file
f4=open('file1.txt')     
lines=f4.readlines()
print(lines)                      
print(len(lines))        # o/p: 4
f4.close()               # o/p: ['-------------- Important things to remember -----------------\n', '-- never do something to impress someone.\n', '-- never live your life on someone else opinions.\n', "-- Just find whatever you love and then hustle untill you don't need to introduce yourself."]


f4=open('file1.txt')                 # o/p: -------------- Important things to remember -----------------
lines=f4.readlines()                 #      -- never do something to impress someone.
for line in lines:                   #      -- never live your life on someone else opinions.
    print(line,end='')               #      -- Just find whatever you love and then hustle untill you don't need to introduce yourself.
f4.close()




# name, closed  ----> data descripter
f4=open('file1.txt')     
print(f4.name)                  # o/p: file1.txt
print(f4.closed)                # o/p: False
f4.close()
print(f4.closed)                # o/p: True





# without using read function, f4 is iterable
f4=open('file1.txt')                 # o/p: -------------- Important things to remember -----------------
for line in f4:                      #      -- never do something to impress someone.
    print(line,end='')               #      -- never live your life on someone else opinions.
f4.close()                           #      -- Just find whatever you love and then hustle untill you don't need to introduce yourself.



# i can make slicing with the help of readlines() method
f4=open('file1.txt')                 # o/p: -------------- Important things to remember -----------------
for line in f4.readlines()[:2]:      #      -- never do something to impress someone.
    print(line,end='')               
f4.close()














# With block  ----> it is used for reading and writing file and many other purposes also
# it is context manager
# in this, we don't need to use close() method to close our file and in add to it, context manager will handle our file in case of damage file

with open("file1.txt") as f5:
    data=f5.read()
    print(data)

print(f5.closed)              # o/p: True

# o/p: 
#      -------------- Important things to remember -----------------
#      -- never do something to impress someone.
#      -- never live your life on someone else opinions.
#      -- Just find whatever you love and then hustle untill you don't need to introduce yourself.







# -------------- Important things to remember -----------------
# -- never do something to impress someone.
# -- never live your life on someone else opinions.
# -- Just find whatever you love and then hustle untill you don't need to introduce yourself.




# 'r' mode ---> used to read file. it is bydefault mode
# 'a' mode ---> append mode, not delet file data, in fact append new data and old data
# 'w' mode ---> override the data(delete the old data and write new data), use when file is empty or we want to delete file data
# 'r+' mode---> we can read and write using this mode, it will not create file, it will start override from starting of the old data but not delete all old data, so we should use seek to set cursor position

# Write to file


# with open("file1.txt",'w') as f6:              # w,a mode also create the file if file is not at location
#     data=f6.write("amckmdla")                        # for a mode--->it will write 1 instead of data in file 




# with open("file1.txt",'r+') as f6:
#     f6.seek(len(f6.read()))
#     f6.write("yash \n ")



















# Read and Write ---> read one file and write those data in another file
# here file1.txt have some data and file2.txt is empty
with open("file1.txt","r") as rf:
    with open("file2.txt","w") as wf:
        wf.write(rf.read())

# when i executed code, file2.txt get data of file1.txt

















# Excercise 1
with open("file1.txt","r") as rf:
    with open("file2.txt","w") as wf:
        for i in rf:
            wf.write(f"{(i).split(',')[0]}\'s salary is {(i).split(',')[1]}")


# OR
with open("file1.txt","r") as rf:
    with open("file2.txt","w") as wf:
        for line in rf.readlines():
            name, salary=line.split(',')
            wf.write(f'{name}\'s salary is {salary}')












# Excercise 2
with open("index.html","r") as rf:
    with open("link.txt","w") as wf:
        for line in rf.readlines():
            if "<a href=" in line:
                pos=line.find("<a href=")
                first_quot=line.find("\"",pos)
                second_quot=line.find("\"",first_quot+1)
                website=line[first_quot+1:second_quot]
                wf.write(website+"\n")





# Better way
with open("index.html","r") as rf:
    with open("link.txt","w") as wf:
        page=rf.read()
        # link_exist=True
        while True:
            pos=page.find("<a href=")
            if pos== -1:
                break
                # link_exist=False
            else:
                first_quot=page.find("\"",pos)
                second_quot=page.find("\"",first_quot+1)
                web=page[first_quot+1:second_quot]
                wf.write(web+"\n")
                page=page[second_quot:]

















# Read Love Story
with open('file1.txt','r') as rf:
    print(rf.encoding)
    data=rf.read()
    print(data)

# # file1.txt
# Love Story
# chat start
# 😘😗😇💓😗
# chat end
# Note - Real friends don't need to send this emojis !
# One more Note - after your family, dogs love human being most but they can't send you emojis !
# Second last note - if someone sends you thse emojis just say :) and don't get over exited !
# Fissl Note - I love you, subscribe to this channel now ! 

# o/p: cp1252
#      Love Story
#      chat start
#      😘😗😇💓😗
#      chat end
#      Note - Real friends don't need to send this emojis !
#      One more Note - after your family, dogs love human being most but they can't send you emojis !
#      Second last note - if someone sends you thse emojis just say :) and don't get over exited !
#      Fissl Note - I love you, subscribe to this channel now !



# to read emojis we should use encoding
with open('file1.txt','r',encoding='utf-8') as rf:
    print(rf.encoding)
    data=rf.read()
    print(data)

# o/p: utf-8
#      Love Story
#      chat start
#      �����😇💓💓😗😗
#      chat end
#      Note - Real friends don't need to send this emojis !
#      One more Note - after your family, dogs love human being most but they can't send you emojis !
#      Second last note - if someone sends you thse emojis just say :) and don't get over exited !
#      Fissl Note - I love you, subscribe to this channel now !









# if our file has number of char and if we read then it will not memory efficient
with open('file1.txt','r') as rf:
    data=rf.read(100)
    print(data)

# o/p: it will return only 100 char from file



# to read whole file
with open('file1.txt','r') as rf:
    data=rf.read(10)
    while(len(data)>0):
        print(data)
        data=rf.read(10)