即使设置为False，布尔值也不会停止条件

Question

For this code :

for crop in database:
    print("The current crop is :", crop)
    x.all_crop_parameters_match_the_PRA_ones = True     

    while x.all_crop_parameters_match_the_PRA_ones :

        ASSESS_Tmin( crop, x, PRA)

        print("x.all_crop_parameters_match_the_PRA_ones = ",  x.all_crop_parameters_match_the_PRA_ones)

        ASSESS_Water( crop, PRA, x)

        print("x.all_crop_parameters_match_the_PRA_ones = ",  x.all_crop_parameters_match_the_PRA_ones)

        ASSESS_pH(crop, PRA, x)

I get the following results:

The current crop is : FBRflx
Checking minimum Temperatures...
x.all_crop_parameters_match_the_PRA_ones =  False

Checking the Water Resources...
Verifying if the Water Resources match with the Tmin supported by the crop...
x.all_crop_parameters_match_the_PRA_ones =  False

The soil pH of this PRA matches to the crop requirements.
This crop is edible for the current PRA !

I don't understand why the programm see that x.all_crop_parameters_match_the_PRA_ones is False and still runs the next functions instead of breaking the loop and switching to the next crop.

x is a class that contains all the variables I use and modify is several functions of my code. Could it be an error because the boolean comes from a class ?

Answer 1

What you post look's like the expected behavior to me. The while loop is going reevaluate the condition only when it executes all code inside it...

If you want the while code to break in the middle, try putting breaks:

for crop in database:
    print("The current crop is :", crop)
    x.all_crop_parameters_match_the_PRA_ones = True     

    while x.all_crop_parameters_match_the_PRA_ones :

        ASSESS_Tmin( crop, x, PRA)

        print("x.all_crop_parameters_match_the_PRA_ones = ",  x.all_crop_parameters_match_the_PRA_ones)

        if not x.all_crop_parameters_match_the_PRA_ones:
            break

        ASSESS_Water( crop, PRA, x)

        print("x.all_crop_parameters_match_the_PRA_ones = ",  x.all_crop_parameters_match_the_PRA_ones)

        if not x.all_crop_parameters_match_the_PRA_ones:
            break

        ASSESS_pH(crop, PRA, x)

Note that it is going to be in a loop the time x.all_crop_parameters_match_the_PRA_ones == True . If you want to execute the code inside while just once, instead of in a loop, you can try:

for crop in database:
    print("The current crop is :", crop)
    x.all_crop_parameters_match_the_PRA_ones = True     

    ASSESS_Tmin( crop, x, PRA)

    print("x.all_crop_parameters_match_the_PRA_ones = ",  x.all_crop_parameters_match_the_PRA_ones)

    if not x.all_crop_parameters_match_the_PRA_ones:
        continue

    ASSESS_Water( crop, PRA, x)

    print("x.all_crop_parameters_match_the_PRA_ones = ",  x.all_crop_parameters_match_the_PRA_ones)

    if not x.all_crop_parameters_match_the_PRA_ones:
        continue 

    ASSESS_pH(crop, PRA, x)