I want to make a function that adds a specific word in front of every string in the array. At the end I want the array changed. I have this code:
def make_great(magicians):
"""Change magicians"""
for magician in magicians:
magician = "the Great" + magician
magicians = ["hudini", "angel", "teller", "anderson", "copperfield"]
make_great(magicians)
print(magicians)
This code doesn't change the array. How can I make my function work?
You can use enumerate to loop over the list with both the index and the value, then use the index to change the value directly into the list:
def make_great(magicians):
for index, magician in enumerate(magicians):
magicians[index] = "the Great " + magician
When you use a for-each loop:
def make_great(magicians):
for magician in magicians:
magician = "The Great" + magician
you're actually creating a new string magician; so modifying it won't modify the original array as you found.
Instead, iterate over the items in the array:
def make_great(magicians):
for i in range(len(magicians)):
magicians[i] = "The Great" + magicians[i]
Or use an enumerator as proposed above. See: How to modify list entries during for loop?
enumerate would be the best thing to do in this case, then modify the value at each index in the array.
for i, magician in enumerate(magicians):
magicians[i] = "the Great " + magician
You can do this with a little Python magic combining lambda and map together
>>> magicians = ['hudini', 'angel', 'teller', 'anderson', 'copperfield']
>>> map(lambda el:'pre_'+el,magicians)
['pre_hudini', 'pre_angel', 'pre_teller', 'pre_anderson', 'pre_copperfield']
Try it out here
