why print() function gives blank list?-CodePudding

I am trying to run this code but I got nothing.Can anyone tell me why It gives nothing.

   thislist = ["apple", "banana", "cherry"]
   for x in thislist:
       thislist.append(x.upper())
   print(thislist)

CodePudding user response：

you are iterating over a list that you are adding to meaning you will never reach the end of the list since every loop you an an extra item. Instead iterate over a slice of the list

thislist = ["apple", "banana", "cherry"]
print(thislist)

for x in thislist[:]:
    thislist.append(x.upper())

print(thislist)

OUTPUT

['apple', 'banana', 'cherry']
['apple', 'banana', 'cherry', 'APPLE', 'BANANA', 'CHERRY']

CodePudding user response：

Use this Code

thislist = ["apple", "banana", "cherry"]
newlist = []
for x in range(len(thislist)):
   newlist.append(thislist[x].upper())
print(newlist)

Happy Learning :)

CodePudding user response：

Because you created an infinite loop. try this:

thislist = ["apple", "banana", "cherry"]
for i in range(len(thislist)):
  thislist[i] = thislist[i].upper()
print(thislist)

And you will get:

['APPLE', 'BANANA', 'CHERRY']