有没有办法在“for”循环中嵌套“if”语句，然后在新列表中返回“True”、“False”或“Unsure”？

Question

I currently have a Series column ("DateDiff") in a DataFrame, and I am trying to create a new list/series next to it that returns "True", "False", or "Unsure" based on the values in the "DateDiff" column.

I've tried to create a nested if function inside a for loop, and then append these returns into a new list named "fraud".

minus = condensed['DEATHDATE'] - condensed['STOP']
minus = minus.tolist()
fraud = []
for value in minus:
    if value in minus > 0:
        fraud.append('True')
    elif value in minus < 0:
        fraud.append('False')
    elif value in minus == 0:
        fraud.append('Unsure')

I'm expecting it to run through each line of [minus], check to see if it is >, <, or == to 0, and then return and append "True", "False", or "Unsure" to the list [list].

Whenever I try to run the code above, I keep getting this error message.

TypeError: '>' not supported between instances of 'list' and 'int'

Answer 1

Since you're already looping through the list, you should be using the variable value to refer to the current item in the iteration. Hence, your if statement should look like this instead:

if value > 0:

Same for the others. Basically, you need to remove the in minus on each line, otherwise its comparing the whole minus list with the number 0, which is not what you want happening.

Answer 2

When using a for loop, you don't need to say if value in minus > 0 . Minus is a list and you cannot compare lists to integers. Instead all you need is if value > 0 since it is already inside the for loop. Your code should look like the following:

minus = condensed['DEATHDATE'] - condensed['STOP']
minus = minus.tolist()
fraud = []
for value in minus:
    if value > 0:
        fraud.append('True')
    elif value < 0:
        fraud.append('False')
    elif value == 0:
        fraud.append('Unsure')

Just a simple misunderstanding in your for loop. Happy Coding!