Debugging - Chapter 8 - Guardian Pattern, and Protecting From Code

### Debugging Assignment ###

# code to be fixed:

han = open('emaildata')

for line in han:

    line = line.rstrip()    # removed white spaces

    words = line.split()    # spliting the line

    if words[0] != 'From':

        continue

    print(words[2])

# --------

    # now after fixing:

han = open('emaildata')

for line in han:

    line = line.rstrip()            # removed white spaces

    print('LINE: ', line)           # print each line to see the whole process going on before T.B.

    words = line.split()            # spliting the line

    print('WORDS: ', words)         # print the splitted line to check at which point program breaks

    # Guardian Pattern

    if len(words) < 1:              # fixing the issue by setting the minimum leve for range to be appropriate.

        continue

    if words[0] != 'From':

        print('ignore')

        continue

    print(words[2])

# Final shape of a clean code

han = open('emaildata')

for line in han:

    line = line.rstrip()

    words = line.split()

    if len(words) < 1:

        continue

    if words[0] != 'From':

        continue

    print(words[2])

# ------------------ alternative approach to creating a guardian

# Alternatively to writing a code for Guradian, there can be to "protect

han = open('emaildata')

for line in han:

    line = line.rstrip()    # removed white spaces

    print('LINE: ', line)

    if line == '':

        print('skipskipskipskipskipskipskipskipskipskipskipskipskipskipskipskipskipskipskipskip')

        continue

    words = line.split()    # spliting the line

    print('WORDS: ', words)

    if words[0] != 'From':

        print('ignore')

        continue

    print(words[2])

# Final code

han = open('emaildata')

for line in han:

    line = line.rstrip()

    if line == '':          # Protecting approach: code for skipping the empty line

        continue

    words = line.split()

    if words[0] != 'From':

        continue

    print(words[2])

# -------------- making guardian a bit stronger

# Guardian approach: making the guardian a bit stronger

# this depends on you judgement and your assumption about the readability of data.

han = open('emaildata')

for line in han:

    line = line.rstrip()

    words = line.split()

    # guardian a bit stronger

    if len(words) < 3:              # changing minimum number from 1 to 3.

        continue

    if words[0] != 'From':

        continue

    print(words[2])

# -------------- making guardian in compound statement

# Guardian approach: creating code for guradian in a compound statement.

# Remamber, the order of code is really important from left to right.

    # if first condition blows-up, the programme will give T.B. so be careful.

han = open('emaildata')

for line in han:

    line = line.rstrip()

    words = line.split()

    # guardian in a compound statement: Order is very important (from left to right).

    if len(words) < 3 or words[0] != 'From':        # means either one of the condition is true, it will skip the line.

        continue

    print(words[2])

##### SUMMARY #####

# As its observed, its not always about a wrong line,

    # debugging can be about adding additional code to support the code already written.

    # there are multiple ways to fix the issue.

        # its always flexible, and depends upon your own capability to write a cleaner, better code.

# Adding a print statement to check upon whats going on is really helpful sometimes.

### Debugging Assignment ###

# code to be fixed:

han = open('emaildata')
for line in han:
    line = line.rstrip()    # removed white spaces
    words = line.split()    # spliting the line
    if words[0] != 'From':
        continue
    print(words[2])
# --------
    # now after fixing:

han = open('emaildata')
for line in han:
    line = line.rstrip()            # removed white spaces
    print('LINE: ', line)           # print each line to see the whole process going on before T.B.
    words = line.split()            # spliting the line
    print('WORDS: ', words)         # print the splitted line to check at which point program breaks
    # Guardian Pattern
    if len(words) < 1:              # fixing the issue by setting the minimum leve for range to be appropriate.
        continue
    if words[0] != 'From':
        print('ignore')
        continue
    print(words[2])

# Final shape of a clean code

han = open('emaildata')
for line in han:
    line = line.rstrip()
    words = line.split()
    if len(words) < 1:
        continue
    if words[0] != 'From':
        continue
    print(words[2])

# ------------------ alternative approach to creating a guardian

# Alternatively to writing a code for Guradian, there can be to "protect

han = open('emaildata')
for line in han:
    line = line.rstrip()    # removed white spaces
    print('LINE: ', line)
    if line == '':
        print('skipskipskipskipskipskipskipskipskipskipskipskipskipskipskipskipskipskipskipskip')
        continue
    words = line.split()    # spliting the line
    print('WORDS: ', words)
    if words[0] != 'From':
        print('ignore')
        continue
    print(words[2])

# Final code
han = open('emaildata')
for line in han:
    line = line.rstrip()
    if line == '':          # Protecting approach: code for skipping the empty line
        continue
    words = line.split()
    if words[0] != 'From':
        continue
    print(words[2])


# -------------- making guardian a bit stronger
# Guardian approach: making the guardian a bit stronger
# this depends on you judgement and your assumption about the readability of data.


han = open('emaildata')
for line in han:
    line = line.rstrip()
    words = line.split()
    # guardian a bit stronger
    if len(words) < 3:              # changing minimum number from 1 to 3.
        continue
    if words[0] != 'From':
        continue
    print(words[2])

# -------------- making guardian in compound statement

# Guardian approach: creating code for guradian in a compound statement.
# Remamber, the order of code is really important from left to right.
    # if first condition blows-up, the programme will give T.B. so be careful.
han = open('emaildata')
for line in han:
    line = line.rstrip()
    words = line.split()
    # guardian in a compound statement: Order is very important (from left to right).
    if len(words) < 3 or words[0] != 'From':        # means either one of the condition is true, it will skip the line.
        continue
    print(words[2])

##### SUMMARY #####

# As its observed, its not always about a wrong line,
    # debugging can be about adding additional code to support the code already written.
    # there are multiple ways to fix the issue.
        # its always flexible, and depends upon your own capability to write a cleaner, better code.
# Adding a print statement to check upon whats going on is really helpful sometimes.