如何仅替换列表的特定部分？

Question

How do I replace apple in the beginning of each string in the list to orange?

Here is what I have tried:

appleList = ['apple_00', 'apple_01', 'apple_02', 'apple_03']

appleList = ['orange' if 'apple' in appleList]

print appleList

Output: ['apple_00', 'apple_01', 'apple_02', 'apple_03']

Desired Output: ['orange_00', 'orange_01', 'orange_02', 'orange_03']

Answer 1

You should use the replace method to modify the strings inside the list:

>>> my_list = ['Apple_00', 'Apple_01', 'Apple_02', 'Apple_03']
>>> print([s.replace('Apple', 'Orange') for s in my_list])

this will print

['Orange_00', 'Orange_01', 'Orange_02', 'Orange_03']

As a side note, you should really use lowercase names for variables per Python Style Guide - PEP08 .

Answer 2

Use replace when an item contains Apple .

This does it:

r = [x.replace('Apple', 'Orange') for x in Register]

print(r)
# ['Orange_00', 'Orange_01', 'Orange_02', 'Orange_03']

Answer 3

You're checking if certain elements in the list are the string 'Apple' , which is obviously never True . you can do it like this:

Register = ['Apple_00', 'Apple_01', 'Apple_02', 'Apple_03']
New_Register = []

for entry in Register:
    New_Register.append(entry.replace('Apple', 'Orange'))

print Register
print New_Register

Or you just use a list comprehension:

Register = ['Apple_00', 'Apple_01', 'Apple_02', 'Apple_03']
Register = [x.replace('Apple', 'Orange') for x in Register]

print Register

Hope this helps!