# Noemi Cabrera # 9 November 2021 # In this lesson, I learned to use .readlines() to read text from files as a list of lines # and use .close() to close a file, which helps to free system resources. Along with these # 2 methods I learned, I used other methods that I learned in previous lessons to perform # the tasks. # I didn't have any difficulties in this lesson.

# [ In this code, a file is imported into this notebook using the curl statement. The name # poem1.txt is given to the file. ] Run to download file to notebook !curl https://raw.githubusercontent.com/MicrosoftLearning/intropython/master/poem1.txt -o poem1.txt

# [ In this code, the imported poem1.txt file is opened in read mode by using open(). Then, # this file is read as a list using the readlines() method and stored in the poem_lines # variable. The list is displayed and we can see the strings include the formatting characters # the file had when imported. ] review and run example # open address to file poem1 = open('poem1.txt', 'r') # readlines and print as a list poem_lines = poem1.readlines() poem_lines

# [ In this code, the for..in loop is used to iterate through each item/string in the poem_lines # list and print each one. The formatting method '\n', which the strings contained, is # applied in the output when printing the strings. ] review and run example for line in poem_lines: print(line)

# [ In this code, a file is imported using a curl statement and named cities.txt.] import cities !curl https://raw.githubusercontent.com/MicrosoftLearning/intropython/master/cities -o cities.txt

# [ In this code, the above imported file is opened in read mode using print() and stored # in the cities_file variable. Then, this file is read as a list using the readlines() method # and stored in the cities_lines variable. ] open cities.txt as cities_file and read the file # as a list: cities_lines cities_file = open("cities.txt", "r") cities_lines = cities_file.readlines()

# [ In this code, the for..in loop iterates through each item in the cities_lines list. Then, # each string is printed along with the '\n' formatting in the output. ] # use list iteration to print each city in cities_lines list for line in cities_lines: print(line)

# In this code, the poem1.txt is re-opened in read mode using the open() method. Then, # this file is read as a list using the readlines() method and stored in the poem_lines # variable. The list is printed. # [ ] review and run examples # [ ] re-open file and read file as a list of strings poem1 = open('poem1.txt', 'r') poem_lines = poem1.readlines() print(poem_lines)

# [ In this code, the for..in loop is used to iterate through each item/string in the poem_lines # list and print each one. The formatting method '\n', which the strings contained, is # applied when printing the strings. ] print each list item for line in poem_lines: print(line)

# [ In this code, the for..in loop is used to remove the last character of each item in the poem_lines # list, which is \n. The variable count is initialized and added 1 each time until there aren't more # items to iterate through. The final list is printed. ] # remove the last character of each list item, which is "\n" count = 0 for line in poem_lines: poem_lines[count] = line[:-1] count += 1 print(poem_lines)

# [ In this code, the for..in loop is used to iterate through each line of the previously # modified poem_lines lis. Then, each line is printed without an added extra new line.] # print each list item for line in poem_lines: print(line)

# In this code, the above imported file is opened in read mode using print() and stored # in the cities_file variable. Then, this file is read as a list using the readlines() method # and stored in the cities_lines variable. # [ ] re-open file and read file as a list of strings # [ ] open cities.txt as cities_file and read the file as a list: cities_lines cities_file = open("cities.txt", "r") cities_lines = cities_file.readlines()

# [ In this code, the for..in loop is used to remove the last character of each item in the cities_lines # list, which is \n. The variable 'iterate' is initialized and added 1 each time until there aren't more # items left to iterate through. The final list is printed. ] # remove the last character, "\n", of each cities_lines list item iterate = 0 for line in cities_lines: cities_lines[iterate] = line[:-1] iterate += 1

# [ In this code, each item/string of the cities_lines list is printed using a for..in loop. # Now, there are no extra new lines in the output since the '\n' formatting characters were # deleted in the previous code cell. ] print each list item in cities_lines for line in cities_lines: print(line)

# [ In this code, the poem1.txt is opened in read mode using the open() method and then stored # in the poem1 variable. ] review and run example: open and readlines of poem1.txt poem1 = open('poem1.txt', 'r')

# [ In this code, the poem1 file opened above is read as a list using the readlines() method # and stored in the poem_lines variable. The list is printed. ] # review and run example: readlines breaks if file is no longer open poem_lines = poem1.readlines() print(poem_lines)

# [In this code, the poem1 file is closed using the .close() method. ] review and run example: Close poem1 poem1.close()

# [ In this code, the imported poem1.txt file is opened in read mode by using open(). ] # open cities.txt as cities_file cities_file = open('cities.txt','r' )

# [ Using the readlines() method, the previous file is read as a list using the readlines() # method and stored in the poem_lines variable. The list is displayed.] # read the lines as cities_lines cities_lines = cities_file.readlines()

# [ In this code, a for..in loop is used to iterate through each item in the cities_lines # list. Then, if the line starts with D or greater, the line is printed. If the line is # less than D, then that line is passed. ] # print the cities that start with the letter "D" or greater for line in cities_lines: if line[0] >= "D": print(line) else: pass

# [ To see if the file is closed or not, I used .readlines() to read the file line by line. # If the file is closed, readlines will break. ] test that file is closed cities_lines =cities_file.readlines() print(cities_lines)

# [ The cities_file is closed using the .close() method. ] close cities_file cities_file.close()

# In this code, a file is imported into this notebook using the curl statement. The name # poem2.txt is given to the file. # [ ] import https://raw.githubusercontent.com/MicrosoftLearning/intropython/master/poem2.txt as poem2.txt !curl https://raw.githubusercontent.com/MicrosoftLearning/intropython/master/poem2.txt -o poem2.txt

# [ In this code, the poem2.txt is opened in read mode using the open() method. ] # open poem2.txt as poem2_text in read mode poem2_text = open("poem2.txt", "r")

# [ Using the readlines() method, the previous file is read as a list using the readlines() # method and stored in the poem2_lines variable. ] # create a list of strings, called poem2_lines, from each line of poem2_text poem2_lines = poem2_text.readlines()

# [ In this code, the for..in loop is used to remove the last character of each item in the poem2_lines # list, which is \n. The variable 'count' is initialized and added 1 each time until there aren't more # items left to iterate through. The final list is printed. ] remove the newline character for each list item in poem2_lines count = 0 for line in poem2_lines: poem2_lines[count] = line[:-1] count += 1 poem2_lines

# [ In this code, a for...in loop is used to iterate through each line in poem2_lines list. # Then, the list is reversed using reverse() and each line is printed in reverse order. ] # print the poem2 lines in reverse order for line in poem2_lines: poem2_lines.reverse() print(line)