python赋值为什么会冒出tuple类型？

Question

import pandas as pd
id_value = 0
l=[]
for i in range(8):
    if i < 3:
        id_value = 1,
    elif 3 <= i <6:
        id_value = 2,
    elif 6 <= i < 9:
        id_value = 3,
    elif 9 <= i <12:
        id_value = 4
    elif 12 <= i < 16:
        id_value = 5
    l.append(id_value)
df = pd.DataFrame(l)
print(df)
df.to_csv('static/data/aaa.csv',index=False)
print('Save Successful!')

1:    为什么上述if判断后的变量id_value值变成tuple类型了？？？

2:    而将上述代码的range()扩大为20000，判断条件也加大了之后，改成下面这样：前面的12000判断出的id_value依旧是tuple类型，但是12000之后的判断出的结果又莫名其妙变成了int类型？？？

3:    我该如何才能避免产生tuple类型的这个bug ???

import pandas as pd
id_value = 0
l=[]
for i in range(20000):
    if i < 4000:
        id_value = 1,
    elif 4000 <= i <8000:
        id_value = 2,
    elif 8000 <= i < 12000:
        id_value = 3,
    elif 12000 <= i <16000:
        id_value = 4
    elif 16000 <= i < 20000:
        id_value = 5
    l.append(id_value)
df = pd.DataFrame(l)
print(df)
df.to_csv('static/data/aaa.csv',index=False)
print('Save Successful!')

 

Answer 1

python不要加标点符号

import pandas as pd
id_value = 0
l=[]
for i in range(8):
    if i < 3:
        id_value = 1
    elif 3 <= i <6:
        id_value = 2
    elif 6 <= i < 9:
        id_value = 3
    elif 9 <= i <12:
        id_value = 4
    elif 12 <= i < 16:
        id_value = 5
    l.append(id_value)
df = pd.DataFrame(l)
print(df)
type(id_value)