coding with files

one diagram for how to open a file

designator for reading

r

designator for writing

w

designator for appending

a

designators for reading/writing/appending binary data

rb, wb, ab

as a designator

r (for reading)

designator for reading and writing to a file

r+

one diagram of how to close a file

one diagram of how to operate on a file with one line of non-indented code

how to write to a file after it has been opened

how writing on to a file works

write will only write a single string
write will write only strings
write will not put a carriage return/new line after writing
(You will need to explicitly put in a newline character (\n) if you want a
newline)

how to open a file in a different directory

how to read from a file one line at a time (this uses a text file)

= .readline() example: next_line = myfile.readline()

how to read multiple lines in a file OPTION 1

for <lineID> in <fileID>:
#do stuff with the string lineID

how to read multiple lines in a file OPTION 2

next_line = myfile.readline()
while next_line != ' ':
# Do stuff with the string next_line
next_line = myfile.readline()

example of reading from and printing a file

how to read from a file in one single string

= .read()

how to convert a file (in code) into a list of strings, with each component representing one line of text from the file

= list() or = .readlines()

how to convert a string into a list of smaller strings, separated by a given character

= .split()

s = "1,2,3,4"
elems = s.split(',')
print(elems)

['1', '2', '3', '4']

how to remove leading and trailing whitespace

.strip()

how to concatenate a list of strings using a separator

.join()

example of string methods being used