How to create the expected list?

Question

I have 3 below lists. I want to create an expected_list that has the same shape with list 1 and will contain element in list 2 if the element in list1 has "Review at", otherwise it will be blank ("")

list1 = [  "Review abcd"
           "Neu"
           "Review defg"
           "Review hmk"
           "hmd"
           "Review lmi"
           "Review yuj"
           "jmf"
           "Review  Bad"]

list2 = [ "http1"
          "http2"
          "http3"
          "http4"
          "http5"
          "http6"]

expected_list = [ "http1"
                  ""
                  "http2"
                  "http3"
                  ""
                  "http4"
                  "http5"
                  ""
                  "http6"]

I tried the following code

for idx, item in enumerate(list1): 
    if "Review" in list1[idx]:
        for j in rang(len(list2))
            expected_list.append(list2[j])
    else:
        expected_list.append("")

However, in each element that satisfies the condition, it appends all the element in list2. So the shape of the expected list is more than expected. I know creating the 2nd loop is wrong. But how can i fix it ?

need comma seperated values

MVB76
– MVB76

2020-12-14 23:07:22 +00:00
Commented Dec 14, 2020 at 23:07 — MVB76
– MVB76, Commented Dec 14, 2020 at 23:07
What have you tried to debug why your code is not working?

Nico Haase
– Nico Haase

2020-12-15 07:03:44 +00:00
Commented Dec 15, 2020 at 7:03 — Nico Haase
– Nico Haase, Commented Dec 15, 2020 at 7:03

juanpa.arrivillaga · Accepted Answer · 2020-12-14 23:08:28Z

1

You simply need something like:

for idx, item in enumerate(list1): 
    if "Review" in item: # use *item* here, that's the whole point of enumerate
        expected_list.append(list2[idx])
    else:
        expected_list.append("")

Better yet, use zip:

for item1, item2 in zip(list1, list2):
    if "Review" in item1:
        expected_list.append(item2)
    else:
        expected_list.append("")

answered Dec 14, 2020 at 23:08

juanpa.arrivillaga

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Comments

MVB76 · Accepted Answer · 2020-12-14 23:36:19Z

1

those lists are one element, you need to seperate values with commas:

also, you dont need a lot of stuff there:

j = 0
for each in list1: 
    if "Review" in each:
        expected_list.append(list2[j])
    else:
        expected_list.append("")
    j+=1

edited Dec 14, 2020 at 23:36

answered Dec 14, 2020 at 23:11

MVB76

1597 bronze badges

1 Comment

mht Over a year ago

thank your. In my case, i should put j+=1 in under the line expected_list.append(list2[j]), because if there is no Review in each review, i dont want the index of list2 to increase. Btw thanks for shedding a light for me.

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