These exercises confused me at first because I was not experienced at building functions, but going through the exercises in class helped me to further understand how to define and build functions. The exercise that gave me the most trouble was list exercise #14. Although I pretty quickly figured out how to use the split and join methods using the examples in the chapter, I had a mistake that tripped me up where instead of referencing new_string when I was defining my final_string I was referencing s (the original string), which I had not performed the split method.
Strings #6: Reverse Function
def reverse(astring):
bstring = ""
for i in xrange(len(astring) -1, -1, -1):
bstring = bstring + astring[i]
return bstring
astring = "happy"
print reverse(astring)
testEqual(reverse("happy"), "yppah")
testEqual(reverse("Python"), "nohtyP")
testEqual(reverse(""), "")
Output:
yppah
Pass
Pass
Pass
Strings #7: Mirror Function
from test import testEqual
def reverse(astring):
bstring = ""
for i in xrange(len(astring) -1, -1, -1):
bstring = bstring + astring[i]
return bstring
def mirror(astring):
return astring + reverse(astring)
astring = "happy"
print mirror(astring)
testEqual(mirror('good'),'gooddoog')
testEqual(mirror('Python'),'PythonnohtyP')
testEqual(mirror(''), '')
testEqual(mirror('a'),'aa')
Output
happyyppah
Pass
Pass
Pass
Pass
Strings #11: Remove First Occurence of Substring
from test import testEqual
def remove(substr,theStr):
#locate the substring
find_substr = theStr.find(substr)
if find_substr < 0: #returns original string if substring doesn't exist
return theStr
#builds new string without substring
remove_substr = theStr[:find_substr] + theStr[find_substr + len(substr):]
return remove_substr
print(remove('pp', 'happy'))
testEqual(remove('an', 'banana'),'bana')
testEqual(remove('cyc', 'bicycle'), 'bile')
testEqual(remove('iss', 'Mississippi'), 'Missippi')
testEqual(remove('egg', 'bicycle'), 'bicycle')
Output
hay
Pass
Pass
Pass
Pass
String #12: Remove All Occurrences of Substring
from test import testEqual
def remove_all(substr,theStr):
remove_substr = theStr.replace(substr, "")
return remove_substr
print(remove_all("iss", "Mississippi"))
testEqual(remove_all('an', 'banana'), 'ba')
testEqual(remove_all('cyc', 'bicycle'), 'bile')
testEqual(remove_all('iss', 'Mississippi'), 'Mippi')
testEqual(remove_all('eggs', 'bicycle'), 'bicycle')
Output
Mippi
Pass
Pass
Pass
Pass
List #7: Count Odd Numbers
def count_odd(list):
#make a counting variable
odd_count = 0
for number in list:
# is it odd
if number % 2 == 1:
odd_count += 1
return odd_count
print(count_odd([5,1,2,3]))
print(count_odd([0,2,6]))
Output
3
0
List #8: Sum Even Numbers
def sum_numbers(list):
even_count = 0
for number in list:
#is it even
if number % 2 == 0:
even_count += number #add up even numbers
return even_count
print(sum_numbers([2,2,2,4,9]))
Output
10
List #9: Sum Negative Numbers
def neg_numbers(list):
neg_count = 0
for number in list:
#is it negative
if number < 0:
neg_count += number #add up negative numbers
return neg_count
print(neg_numbers([-1,2,-9,4,9]))
Output
-10
List #14: Replacing Old with New
def replace(s, old, new):
#splits string at old
new_string = s.split(old)
#adds new occurences
glue = new
final_string = glue.join(new_string)
return final_string
print(replace('happy', 'p', 'P'))
print(replace('Mississippi', 'i', 'I'), 'MIssIssIppI')
s = 'I love spom! Spom is my favorite food. Spom, spom, spom, yum!'
print(replace(s, 'om', 'am'))
print(replace(s, 'o', 'a'))
Output
haPPy
MIssIssIppI MIssIssIppI
I love spam! Spam is my favorite food. Spam, spam, spam, yum! I love spam! Spam is my favorite food. Spam, spam, spam, yum!
I lave spam! Spam is my favarite faad. Spam, spam, spam, yum! I lave spam! Spam is my favarite faad. Spam, spam, spam, yum!