webinar-files-2023-05-13

# Files 2023 5 13

# FILES!!!

# Ch 14 Labs to 100%, watch Submit Mode unit tests
# file questions on Prac Tests, Ch 33-34, and the Pre
# Ch 31 do at least 31.2 (I called this 32.2 today... I meant 31.2, the movie show times Lab)

# create a file object
# ... with the open()
# we get access to file object methods: read(), readlines(), write()

# MODES
# READ
# WRITE
# APPEND

# READ MODE
# filename = input()
with open("test.txt", "r") as f:
    contents = f.readlines() # list of strings, line by line

print(contents) # ['Hello.\n', 'This\n', 'is\n', 'just\n', 'a\n', 'string.\n', 'But...\n', 'with\n', 'many\n', 'line\n', 'breaks!']

# for line in contents:
#     print(line) # one /n in the string itself, and another from print()

# for line in contents:
#     line = line.strip()
#     print(line)

# CSV Module
# reader() method
import csv
with open("mock_data.csv", "r") as f1:
    # contents = f.readlines()  # list of strings, line by line
    contents = list(csv.reader(f1)) # for tsv files csv.reader(f1, delimiter="\t")
# print(contents) # a list of lists... [['id', 'first_name', 'last_name', 'email', 'gender', 'ip_address'], ['1', 'Remington', 'Shilling', 'rshilling0@wsj.com', 'Male', '1.71.141.52']...
# for row in contents[0:20]:
#     print(row)

# WRITE MODE
with open("output_data3.csv", "w") as f2:
    # write a new csv with rows from this one where last name starts with R
    for row in contents:
        # last name is position 2 of inner list: row[2]
        if row[2][0] == "R": # if row[2][0].lower() == "r": # if row[2].startswith("R"):
            # take action! Write to the new file
            f2.write(",".join(row)+"\n") # write() method takes one single str argument

# APPEND MODE
# "Let's write one more row onto the end of that previous file
# ['1', 'Remington', 'Shilling', 'rshilling0@wsj.com', 'Male', '1.71.141.52']
with open("output_data3.csv", "a") as f2:
    f2.write("1001,Shilling,Remington,sremington@wsj.com,Male,1.71.141.53\n")



# You can get mock data like the kind in my first csv:
# www.mockaroo.com