How to do something else at the end of an iteration-CodePudding

I have a list that contains some strings , I want to add some predefined values before every string in a list but the value at the end of the iteration should be different

Here is the list

lst = ['USER_INVITE','USER_LEAVE','GIVEAWAY_START','GIVEAWAY_EDIT','USER_INVITE','USER_LEAVE']

the expected output is

<:878677713269968896:909470525108154399> USER_INVITE
<:878677713269968896:909470525108154399> USER_LEAVE
<:878677713269968896:909470525108154399> GIVEAWAY_START
<:878677713269968896:909470525108154399> GIVEAWAY_EDIT
<:878677713269968896:909470525108154399> USER_INVITE
<:878677686350934027:910454682219085834> USER_LEAVE

here you can see the value before USER_LEAVE is different than others

I can simply do something like this to put these values before strings without a loop

logs = '<:878677713269968896:909470525108154399>\n'.join(map(str,keys[I]))

maybe iteration will help in this case by doing something else at the end of the loop

CodePudding user response：

Using iteration, and some control flow logic around identifying the last item in the list, this can be done as follows:

output_str = ""

for i, item in enumerate(lst):
    if i == len(lst) - 1:  # Logic for identifying the last element
        prefix = '<:878677686350934027:910454682219085834>'
    else:  # If not the last element in the list, do this:
         prefix = '<:878677713269968896:909470525108154399>'
    
    output_str  = f'{prefix} {item}\n'

CodePudding user response：

output_str = ""

for item in lst[:-1]:
    output_str  = f'<:878677686350934027:910454682219085834> {item}\n'
output_str  = f'<:878677713269968896:909470525108154399> {lst[-1]}'

CodePudding user response：

You can just work on every key but the last and then combine the output at the end.

a = "\n".join('<:878677713269968896:909470525108154399>'   key for key in lst[:-1])
b = '<:878677686350934027:910454682219085834>'   lst[-1]
a   b

'<:878677713269968896:909470525108154399>USER_INVITE\n<:878677713269968896:909470525108154399>USER_LEAVE\n<:878677713269968896:909470525108154399>GIVEAWAY_START\n<:878677713269968896:909470525108154399>GIVEAWAY_EDIT\n<:878677713269968896:909470525108154399>USER_INVITE<:878677686350934027:910454682219085834>USER_LEAVE'