To create a directory, use the os.mkdir() function. This function creates a new directory at the specified path.
import os
# Create a directory named "example_dir"
os.mkdir("example_dir")
If you need to create multiple nested directories, use os.makedirs().
import os
# Create nested directories
os.makedirs("parent_dir/child_dir")
To rename a directory, use the os.rename() function. This function renames the directory from the old name to the new name.
import os
# Rename the directory from "example_dir" to "new_example_dir"
os.rename("example_dir", "new_example_dir")
To move a directory, use the shutil.move() function from the shutil module. This function moves the directory to the specified destination.
import shutil
# Move the directory to a new location
shutil.move("new_example_dir", "moved_example_dir")
To check if a directory exists, use the os.path.exists() function. This function returns True if the directory exists, and False otherwise.
import os
# Check if the directory exists
if os.path.exists("moved_example_dir"):
print("Directory exists")
else:
print("Directory does not exist")
To list all directories in a given path, use the os.listdir() function. This function returns a list of all files and directories in the specified path.
import os
# List all directories in the current directory
directories = [d for d in os.listdir(".") if os.path.isdir(d)]
print(directories)
To delete a directory, use the os.rmdir() function for an empty directory, or shutil.rmtree() for a directory that may contain files and subdirectories.
import os
import shutil
# Remove an empty directory
os.rmdir("empty_dir")
# Remove a directory with contents
shutil.rmtree("dir_with_contents")
To read from a file, use the open() function with the r mode and then use the read(), readline(), or readlines() methods.
with open("example.txt", "r") as file:
content = file.read()
print(content)
with open("example.txt", "r") as file:
for line in file:
print(line.strip())
To write to a file, use the open() function with the w mode and then use the write() or writelines() methods.
with open("example.txt", "w") as file:
file.write("Hello, world!")
To append to a file, use the open() function with the a mode.
with open("example.txt", "a") as file:
file.write("\nThis is an appended line.")
To copy the contents of one file to another, use the shutil.copyfile() function.
import shutil
shutil.copyfile("source.txt", "destination.txt")
To merge the contents of two files, read both files and write their contents to a new file.
with open("file1.txt", "r") as file1, open("file2.txt", "r") as file2, open("merged.txt", "w") as merged_file:
merged_file.write(file1.read() + "\n" + file2.read())
To read a list of space-separated integers, use the input() function and then split and convert the input.
input_string = input("Enter space-separated integers: ")
numbers = list(map(int, input_string.split()))
print(numbers)
To read multiple lines of input, use a loop that reads each line until a termination condition is met.
print("Enter lines of text (type 'STOP' to end):")
lines = []
while True:
line = input()
if line == "STOP":
break
lines.append(line)
print(lines)
In programming, input is often given as multiple lines, where the first line contains an integer n, followed by n lines of data.
n = int(input())
data = []
for _ in range(n):
data.append(input().strip())
print(data)
Problem 1: Given a file with path filename containing a list of integers separated by spaces, write a Python program to read the file and print the sum of the integers.
# Read the file and calculate the sum of integers
def sum_integers(filename):
pass
Problem 2: Write a Python program that reads a file input_file containing a list of words separated by spaces and writes the unique words to a new file output_file, each on a new line in alphabetical order.
# Read the file and write unique words to a new file
def unique_words(input_file, output_file):
pass
Problem 3: Read a file input_file containing a variable number of space-separated strings in each line, in a word-by-word manner. When the word "STOP" is encountered, among these strings, stop reading the file and write each word read in input_file before "STOP" along with its frequency. Write the output to a new file output_file in the format word: frequency.
# Read the file and write word frequencies to a new file
def word_frequencies(input_file, output_file):
pass
# Example Test case
# input.txt:
# apple banana apple cherry
# mango apple banana STOP panda goose
# pumpkin apple cherry
# output.txt:
# apple: 3
# banana: 2
# cherry: 1
# mango: 1
Problem 4: Given a list of directories dirs, write a Python program to create these directories if they do not exist. If the directories already exist, print a message indicating that the directory already exists. In each directory, create a file named README.md with the content "This is a README file for directory dir_name", where dir_name is the name of the directory.
# Create directories and README files
def create_directories(dirs):
pass
Problem 5: Modify line within file filename by replacing the line at index line_number(startin line is at index 1) with the new line new_line. Check if the line number is valid and return True if the line was modified successfully, False otherwise.
def modify_line(filename, line_number, new_line):
pass
Problem 6: Read CSV file. Given a file filename in the CSV format, write a Python program to read the file and return a dictionary where each dictionary represents a column with dictionary key as the column header and the value as a list of values in that column. The first row of the CSV file contains the column headers, separated by a comma. The subsequent rows contain the data, also separated by commas. The data in each row corresponds to the column header in the same position.
# Read the CSV file and return a list of dictionaries
def read_csv(filename):
pass
# Example Test case
# filename: data.csv
# Name,Age,Gender
# Alice,25,F
# Bob,30,M
# Charlie,35,M
# David,40,M
# Output:
# {'Name': ['Alice', 'Bob', 'Charlie', 'David'], 'Age': ['25', '30', '35', '40'], 'Gender': ['F', 'M', 'M', 'M']}
Problem 7: Write a Python program that reads all files within the current directory and does the following:
It checks the file's extension and categorizes the files into different lists based on the extension. Files having no extensions are also a separate category. An extension is the part of the filename after the last dot.
For each category, it creates a new directory(if such a directory already does not exist) with the name of the directories being the extension name. It then moves the files to the corresponding directories.
# Categorize files based on extension and move them to directories
def categorize_files():
pass
Problem 8: Directory synchronization: Given two directories dir1 and dir2, write a Python program to synchronize the contents of the two directories. The program should do the following:
dir1 but not in dir2, copy the file/folder from dir1 to dir2.dir2 but not in dir1, copy the file/folder from dir2 to dir1.dir2 with the file from dir1.# Synchronize directories
def synchronize_directories(dir1, dir2):
pass