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Python Python Basics (2015) Letter Game App Letter Game Introduction

Sebastiaan van Vugt
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Sebastiaan van Vugt
Python Development Techdegree Graduate 13,554 Points
Posted by Sebastiaan van Vugt
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Sebastiaan van Vugt
Python Development Techdegree Graduate 13,554 Points

Variable in a loop is updated continuously - before it is supposed to do so.

Summarised my problematic code is sth like:

while True:
    if aa:
    if bb:
    elif x:
    elif y:
    elif z:
    else:
        for a in range (0, (len(secret_word))):
            for guess in guess_list:
                if secret_list[a] == guess:
                    progress_list[a] = guess
        if progress_list != progress_list2:
            print("There is a '{}' in the secret word indeed :)\n".format(guess))                
            b +=1
        else:
            color.write("The letter '{}' is not in the secret word.\n".format(guess),"COMMENT")
        progress_list2 = progress_list ```

The first time python goes through this loop it is possible that progress_list != progress_list2 but the second time this becomes impossible. The progress_list should be updated before progress_list2 and therefore it should be possible to continue entering if progress_list != progress_list2. When printing the progress_list and progress_list2 during the loop one can, however, see that only the first time around the lists can be different and that the second and following times they are updated simultaneously. Does anyone have an explanation for this?

The full code can be found here: https://codeshare.io/a3vPdg

Thanks a lot!

1 Answer

Sebastiaan van Vugt
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Sebastiaan van Vugt
Python Development Techdegree Graduate 13,554 Points
Sebastiaan van Vugt
.a{fill-rule:evenodd;}techdegree seal-36
Sebastiaan van Vugt
Python Development Techdegree Graduate 13,554 Points

This website helped me understand how variables are bound in Python: python-variables

These examples explain how variables are bound in Python:

Appending a will append b

a = [1, 2]
b = a
a.append(3)
print("a = {}".format(a))
print("b = {}".format(b))

result: a = [1, 2, 3] b = [1, 2, 3]

Variables are bound and not equated i.e. this works in one direction

a = [1, 2]
a = b
a.append(3)
print("a = {}".format(a))
print("b = {}".format(b))

result: NameError: name 'b' is not defined

a is bound anew

b = [9]
a = [1, 2]
a = b
a.append(3)
print("a = {}".format(a))
print("b = {}".format(b))

result: a = [9, 3] b = [9, 3]

a substitution in a will substitute in b

a = [1, 2]
b = a
a.append(3)
a[1]=9
print("a = {}".format(a))
print("b = {}".format(b))

result: a = [1, 9, 3] b = [1, 9, 3]

b is bound anew

a = [1, 2]
b = a
a.append(3)
a[1]=9
b = [10]
print("a = {}".format(a))
print("b = {}".format(b))

result: a = [1, 9, 3] b = [10]