replace a certain value of specific key in list of dictionaries python-CodePudding

I have a list of dictionaries

list1 = [{'time': '2020', 'name': 'one', 'address': '15423'},{'time': '2021', 'name': 'two', 'address': '8548305'}, {'time': '2019', 'name': 'five', 'address': '15423'}]

I want to convert anything that has address with 15423 to 'Valid' and all the other cases Invalid Final output

list1 = [{'time': '2020', 'name': 'one', 'address': 'Valid'},{'time': '2021', 'name': 'two', 'address': 'Invalid'}, {'time': '2019', 'name': 'five', 'address': 'Valid'}]

Here is what I tried

if '15423' in list1['address']:
    list1['address'] = 'Valid'
else:
    list1['address'] = 'Invalid'

But I am not sure why it is not working. Maybe I need to loop through the whole column. Appreciate your help

CodePudding user response：

You need to iterate over the elements of list1 using a for loop, since list1 is a list of dictionaries:

for i in range(len(list1)):
    if '15423' in list1[i]['address']:
        list1[i]['address'] = 'Valid'
    else:
        list1[i]['address'] = 'Invalid'
        
print(list1)

You can also condense the if/else into a ternary if you're looking for a more concise solution:

for i in range(len(list1)):
    list1[i]['address'] = 'Valid' if '15423' in list1[i]['address'] else 'Invalid'

Both of these print:

[{'time': '2020', 'name': 'one', 'address': 'Valid'},
{'time': '2021', 'name': 'two', 'address': 'Invalid'},
{'time': '2019', 'name': 'five', 'address': 'Valid'}]

CodePudding user response：

you have to loop through the list!

Why?

let's say num_list = [0, 1, 2, 3]

using a for loop like so:

for item in num_list:
    ...

will loop through num_list as you'd expect. item will be set to the current value, in this case, it will set item to 1, do the code in the loop, then set item to 2, then do the code in the loop again, and so on.

now let's say num_list = [{"number": 0}, {"number": 1}, {"number": 2}, {"number": 3}].

this time, if you run the same for loop, item will still be set to the current value, in this case, it will set it to the dictionary instead of the number. thus, item is set to {"number": 0}, then the code inside the loop will run, then item is set to {"number": 1}, then the code inside the loop will run again, etc.

thus, item will be set to a dictionary, which by then you can edit like any other dictionary! simply do item["number"] = ...

for the actual fixed code, here ya go

list1 = [
    {'time': '2020', 'name': 'one', 'address': '15423'},
    {'time': '2021', 'name': 'two', 'address': '8548305'},
    {'time': '2019', 'name': 'five', 'address': '15423'}
]


for item in list1:
    if item["address"] == "15423":
        item["address"] = "Valid"
    else:
        item["address"] = "Invalid"

print(list1)

output:

[
    {'time': '2020', 'name': 'one', 'address': 'Valid'},
    {'time': '2021', 'name': 'two', 'address': 'Invalid'},
    {'time': '2019', 'name': 'five', 'address': 'Valid'}
]