Python Help For Beginner

[BrettAuger1]

Hi folks,

Another python question for the forum, this one should be easy. I am trying to complete the following exercise and am stumped with the last section. I am asked to print only the items in the list with exactly 5 characters. If anyone can help me out that would be much appreciated.

# Create list with these four entries: roads, streams, parks, contours value1 = "roads" value2 = "streams" value3 = "parks" value4 = "contours"  List = [value1, value2, value3, value4]  # Print the first entry in the list to the interactive window print List[0]  # Use a loop to print every entry that has exactly 5 # characters to the interactive window  print List 

Thanks,

Brett

[Anonymous User · Accepted solution]

Python has a length() test:

# Create list with these four entries: roads, streams, parks, contours
value1 = "roads"
value2 = "streams"
value3 = "parks"
value4 = "contours"

List = [value1, value2, value3, value4]

# Print the first entry in the list to the interactive window
print List[0]

# Use a loop to print every entry that has exactly 5
for val in List:
    if len(val) == 5:
        print '{0} has a length of 5 characters'.format(val)
# characters to the interactive window

[BrettAuger1]

Perfect, works just fine.

Thank you.

[JamesCrandall]

Or...

List = [value1, value2, value3, value4]
matches = [s for s in List if len(s)==5]
for m in matches:
  print m

[JamesCrandall]

Even more pythonic:

value1 = "roads"
value2 = "streams"
value3 = "parks"
value4 = "contours"

List = [value1, value2, value3, value4]

for match in [s for s in List if len(s)==5]:
    print match

[Anonymous User]

Even more pythonic:

value1 = "roads"
value2 = "streams"
value3 = "parks"
value4 = "contours"

List = [value1, value2, value3, value4]

for match in [s for s in List if len(s)==5]:
    print match

Thanks James.  This is definitely the better answer, but list comprehensions are probably not very easy to understand for a beginner.

[JamesCrandall]

Thanks James.  This is definitely the better answer, but list comprehensions are probably not very easy to understand for a beginner.

Heck, I still struggle with them!

OP -- Caleb's answer is exactly how I have it in 99% of my code but I'm starting to write in a more pythonic style.  I just thought a different approach would be good to see!