#!/usr/bin/env python
# coding: utf-8

# # Reading and Writing files

# In[1]:


f = open("file-demo-read.txt", "r")
data = f.read()
print(data)
f.close()


# # More clean way. The close method will be implicitly called just before exiting with block.

# In[2]:


with open("file-demo-read.txt", "r") as f:
    data = f.read()

print(data)


# # Reading one line at a time

# In[3]:


with open("file-demo-read.txt", "r") as f:
    data = f.readline()

print(data)


# # Writing into file

# In[4]:


f = open("file-demo-write.txt", "r+")
f.write("This is a sample text.")
f.close()


# ### Reading the written content

# In[5]:


f = open("file-demo-write.txt", "r")
data = f.read()
print(data)
f.close()


# # File positioning

# In[6]:


f = open("file-demo-write.txt", "r")
f.seek(5)
data = f.readline()
print(data)
f.seek(0)
data = f.readline()
print(data)
f.close()


# # File system operations

# In[7]:


import os


# ### Create a directory

# In[8]:


os.mkdir("demo")


# ### Rename a directory

# In[9]:


os.rename("demo", "demo-dir")


# ### Change current working directory

# In[10]:


curr_dir_backup = os.getcwd()
os.chdir("demo-dir")


# ### Print current working directory

# In[11]:


curr_dir = os.getcwd()
print(curr_dir)


# ### Create a file under this directory

# In[12]:


f= open("demo.txt","w+")
f.close()


# ### Rename this file

# In[13]:


os.rename("demo.txt", "demo-file.txt")


# ### Create two directory under this directory

# In[14]:


os.mkdir("demo-sub-dir-1")
os.mkdir("demo-sub-dir-2")


# ### List all files and directories

# In[15]:


dir_list = os.listdir()
print(dir_list)


# ### Get the statistics of a director. Current directory in the case below.

# In[16]:


stat = os.stat(".")
print(stat)


# ## Clean up

# In[17]:


if(os.path.exists("../demo-dir")):
    if(os.path.exists("demo-sub-dir-1")):
        os.rmdir("demo-sub-dir-1")
    if(os.path.exists("demo-sub-dir-2")):
        os.rmdir("demo-sub-dir-2")
    if(os.path.isfile("demo-file.txt")):
        os.remove("demo-file.txt")
    os.rmdir("../demo-dir")
os.chdir(curr_dir_backup)