In [1]:

    

path = 'data/src/test.txt'


    

In [2]:

    

f = open(path)


    

In [3]:

    

print(type(f))


    

    




<class '_io.TextIOWrapper'>

In [4]:

    

f.close()


    

In [5]:

    

with open(path) as f:
    print(type(f))


    

    




<class '_io.TextIOWrapper'>

In [6]:

    

# with open('data/src/test_error.txt') as f:
#     print(type(f))
# FileNotFoundError: [Errno 2] No such file or directory: 'data/src/test_error.txt'


    

In [7]:

    

with open(path) as f:
    s = f.read()
    print(type(s))
    print(s)


    

    




<class 'str'>
line 1
line 2
line 3

In [8]:

    

with open(path) as f:
    s = f.read()

print(s)


    

    




line 1
line 2
line 3

In [9]:

    

with open(path) as f:
    l = f.readlines()
    print(type(l))
    print(l)


    

    




<class 'list'>
['line 1\n', 'line 2\n', 'line 3']

In [10]:

    

with open(path) as f:
    l_strip = [s.strip() for s in f.readlines()]
    print(l_strip)


    

    




['line 1', 'line 2', 'line 3']

In [11]:

    

with open(path) as f:
    l = f.readlines()
    print(l[1])


    

    




line 2

In [12]:

    

with open(path) as f:
    for s_line in f:
        print(s_line)


    

    




line 1

line 2

line 3

In [13]:

    

with open(path) as f:
    s_line = f.readline()
    print(s_line)


    

    




line 1

In [14]:

    

with open(path) as f:
    while True:
        s_line = f.readline()
        print(s_line)
        if not s_line:
            break


    

    




line 1

line 2

line 3

In [15]:

    

path_w = 'data/src/test_w.txt'


    

In [16]:

    

s = 'New file'

with open(path_w, mode='w') as f:
    f.write(s)

with open(path_w) as f:
    print(f.read())


    

    




New file

In [17]:

    

# with open('data/src/new_dir/test_w.txt', mode='w') as f:
#     f.write(s)
# FileNotFoundError: [Errno 2] No such file or directory: 'data/src/new_dir/test_w.txt'


    

In [18]:

    

s = 'New line 1\nNew line 2\nNew line 3'

with open(path_w, mode='w') as f:
    f.write(s)

with open(path_w) as f:
    print(f.read())


    

    




New line 1
New line 2
New line 3

In [19]:

    

l = ['One', 'Two', 'Three']

with open(path_w, mode='w') as f:
    f.writelines(l)

with open(path_w) as f:
    print(f.read())


    

    




OneTwoThree

In [20]:

    

with open(path_w, mode='w') as f:
    f.write('\n'.join(l))

with open(path_w) as f:
    print(f.read())


    

    




One
Two
Three

In [21]:

    

# with open(path_w, mode='x') as f:
#     f.write(s)
# FileExistsError: [Errno 17] File exists: 'data/src/test_w.txt'


    

In [22]:

    

try:
    with open(path_w, mode='x') as f:
        f.write(s)
except FileExistsError:
    pass


    

In [23]:

    

import os

if not os.path.isfile(path_w):
    with open(path_w, mode='w') as f:
        f.write(s)


    

In [24]:

    

with open(path_w, mode='a') as f:
    f.write('Four')

with open(path_w) as f:
    print(f.read())


    

    




One
Two
ThreeFour

In [25]:

    

with open(path_w, mode='a') as f:
    f.write('\nFour')

with open(path_w) as f:
    print(f.read())


    

    




One
Two
ThreeFour
Four

In [26]:

    

with open(path_w, mode='r+') as f:
    f.write('123456')

with open(path_w) as f:
    print(f.read())


    

    




123456o
ThreeFour
Four

In [27]:

    

with open(path_w, mode='r+') as f:
    f.seek(3)
    f.write('-')

with open(path_w) as f:
    print(f.read())


    

    




123-56o
ThreeFour
Four

In [28]:

    

with open(path_w) as f:
    l = f.readlines()

l.insert(0, 'FIRST\n')

with open(path_w, mode='w') as f:
    f.writelines(l)

with open(path_w) as f:
    print(f.read())


    

    




FIRST
123-56o
ThreeFour
Four