Learn to Program 6

Posted by Derek Banas on Jul 6, 2016 in Web Design | 0 comments

In this part of my Learn to Program series we cover one of the most important topics which is lists.We’ll look at numerous list functions, how to sort lists with the Bubble Sort, List Comprehensions, simple Debugging and much more.

This tutorial series is all about learning how to solve problems, and those problems get more complex with each tutorial. Make sure you watch the first part before moving on. The code follows the video below.

If you like videos like this consider contributing a dollar on Patreon.

Code & Transcript

# ---------- LEARN TO PROGRAM 6 ----------

import random
import math

# With lists we can refer to groups of data with 1 name

# Each item in the list corresponds to a number (index)
# just like how people have identification numbers.
# By default the 1st item in a list has the index 0

# [0 : "string"] [1 : 1.234] [2 : 28] [3 : "c"]

# Python lists can grow in size and can contain data
# of any type

randList = ["string", 1.234, 28]

# Create a list with range
oneToTen = list(range(10))

# An awesome thing about lists is that you can use many
# of the same functions with them that you used with strings

# Combine lists
randList = randList + oneToTen

# Get the 1st item with an index
print(randList[0])

# Get the length
print("List Length :", len(randList))

# Slice a list to get 1st 3 items
first3 = randList[0:3]

# Cycle through the list and print the index
for i in first3:
    print("{} : {}".format(first3.index(i), i))

# You can repeat a list item with *
print(first3[0] * 3)

# You can see if a list contains an item
print("string" in first3)

# You can get the index of a matching item
print("Index of string :", first3.index("string"))

# Find out how many times an item is in the list
print("How many strings :", first3.count("string"))

# You can change a list item
first3[0] = "New String"

for i in first3:
    print("{} : {}".format(first3.index(i), i))

# Append a value to the end of a list
first3.append("Another")

# ---------- PROBLEM : CREATE A RANDOM LIST ----------
# Generate a random list of 5 values between 1 and 9
numList = []
for i in range(5):
    numList.append(random.randrange(1, 9))

# ---------- SORT A LIST : BUBBLE SORT ----------
# The Bubble sort is a way to sort a list
# It works this way
# 1. An outer loop decreases in size each time
# 2. The goal is to have the largest number at the end of
#    the list when the outer loop completes 1 cycle
# 3. The inner loop starts comparing indexes at the beginning
#    of the loop
# 4. Check if list[Index] > list[Index + 1]
# 5. If so swap the index values
# 6. When the inner loop completes the largest number is at
#    the end of the list
# 7. Decrement the outer loop by 1

# Create the value that will decrement for the outer loop
# Its value is the last index in the list
i = len(numList) - 1

while i > 1:

    j = 0

    while j < i:

        # Tracks the comparison of index values
        print("\nIs {} > {}".format(numList[j], numList[j+1]))
        print()

        # If the value on the left is bigger switch values
        if numList[j] > numList[j+1]:

            print("Switch")

            temp = numList[j]
            numList[j] = numList[j + 1]
            numList[j + 1] = temp

        else:
            print("Don't Switch")

        j += 1

        # Track changes to the list
        for k in numList:
            print(k, end=", ")
        print()

    print("END OF ROUND")

    i -= 1

for k in numList:
    print(k, end=", ")
print()

# ---------- MORE LIST FUNCTIONS ----------
numList = []
for i in range(5):
    numList.append(random.randrange(1, 9))

# Sort a list
numList.sort()

# Reverse a list
numList.reverse()

for k in numList:
    print(k, end=", ")
print()

# Insert value at index insert(index, value)
numList.insert(5, 10)

# Delete first occurrence of value
numList.remove(10)

for k in numList:
    print(k, end=", ")
print()

# Remove item at index
numList.pop(2)

for k in numList:
    print(k, end=", ")
print()

# ---------- LIST COMPREHENSIONS ----------
# You can construct lists in interesting ways using
# list comprehensions

# Perform an operation on each item in the list

# Create a list of even values
evenList = [i*2 for i in range(10)]

for k in evenList:
    print(k, end=", ")
print()

# List of lists containing values to the power of
# 2, 3, 4
numList = [1,2,3,4,5]

listOfValues = [[math.pow(m, 2), math.pow(m, 3), math.pow(m, 4)]
                for m in numList]

for k in listOfValues:
    print(k)
print()

# Create a 10 x 10 list
multiDList = [[0] * 10 for i in range(10)]

# Change a value in the multidimensional list
multiDList[0][1] = 10

# Get the 2nd item in the 1st list
# It may help to think of it as the 2nd item in the 1st row
print(multiDList[0][1])

# Get the 2nd item in the 2nd list
print(multiDList[1][1])

# ---------- MULTIDIMENSIONAL LIST ----------

# Show how indexes work with a multidimensional list
listTable = [[0] * 10 for i in range(10)]

for i in range(10):

    for j in range(10):
        listTable[i][j] = "{} : {}".format(i, j)

for i in range(10):

    for j in range(10):
        print(listTable[i][j], end=" || ")
    print()

# ---------- PROBLEM : CREATE MULTIPLICATION TABLE ----------
# With 2 for loops fill the cells in a multidimensional
# list with a multiplication table using values 1 - 9
'''
1, 2, 3, 4, 5, 6, 7, 8, 9,
2, 4, 6, 8, 10, 12, 14, 16, 18,
3, 6, 9, 12, 15, 18, 21, 24, 27,
4, 8, 12, 16, 20, 24, 28, 32, 36,
5, 10, 15, 20, 25, 30, 35, 40, 45,
6, 12, 18, 24, 30, 36, 42, 48, 54,
7, 14, 21, 28, 35, 42, 49, 56, 63,
8, 16, 24, 32, 40, 48, 56, 64, 72,
9, 18, 27, 36, 45, 54, 63, 72, 81
'''

# Create the multidimensional list
multTable = [[0] * 10 for i in range(10)]

# This will increment for each row
for i in range(1, 10):

    # This will increment for each item in the row
    for j in range(1, 10):

        # Assign the value to the cell
        multTable[i][j] = i * j

# Output the data in the same way you assigned it
for i in range(1, 10):

    for j in range(1, 10):
        print(multTable[i][j], end=", ")

    print()

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

# ---------- LEARN TO PROGRAM 6 ----------

import random

import math

# With lists we can refer to groups of data with 1 name

# Each item in the list corresponds to a number (index)

# just like how people have identification numbers.

# By default the 1st item in a list has the index 0

# [0 : "string"] [1 : 1.234] [2 : 28] [3 : "c"]

# Python lists can grow in size and can contain data

# of any type

randList = ["string", 1.234, 28]

# Create a list with range

oneToTen = list(range(10))

# An awesome thing about lists is that you can use many

# of the same functions with them that you used with strings

# Combine lists

randList = randList + oneToTen

# Get the 1st item with an index

print(randList[0])

# Get the length

print("List Length :", len(randList))

# Slice a list to get 1st 3 items

first3 = randList[0:3]

# Cycle through the list and print the index

for i in first3:

print("{} : {}".format(first3.index(i), i))

# You can repeat a list item with *

print(first3[0] * 3)

# You can see if a list contains an item

print("string" in first3)

# You can get the index of a matching item

print("Index of string :", first3.index("string"))

# Find out how many times an item is in the list

print("How many strings :", first3.count("string"))

# You can change a list item

first3[0] = "New String"

for i in first3:

print("{} : {}".format(first3.index(i), i))

# Append a value to the end of a list

first3.append("Another")

# ---------- PROBLEM : CREATE A RANDOM LIST ----------

# Generate a random list of 5 values between 1 and 9

numList = []

for i in range(5):

numList.append(random.randrange(1, 9))

# ---------- SORT A LIST : BUBBLE SORT ----------

# The Bubble sort is a way to sort a list

# It works this way

# 1. An outer loop decreases in size each time

# 2. The goal is to have the largest number at the end of

# the list when the outer loop completes 1 cycle

# 3. The inner loop starts comparing indexes at the beginning

# of the loop

# 4. Check if list[Index] > list[Index + 1]

# 5. If so swap the index values

# 6. When the inner loop completes the largest number is at

# the end of the list

# 7. Decrement the outer loop by 1

# Create the value that will decrement for the outer loop

# Its value is the last index in the list

i = len(numList) - 1

while i > 1:

j = 0

while j < i:

# Tracks the comparison of index values

print("\nIs {} > {}".format(numList[j], numList[j+1]))

print()

# If the value on the left is bigger switch values

if numList[j] > numList[j+1]:

print("Switch")

temp = numList[j]

numList[j] = numList[j + 1]

numList[j + 1] = temp

else:

print("Don't Switch")

j += 1

# Track changes to the list

for k in numList:

print(k, end=", ")

print()

print("END OF ROUND")

i -= 1

for k in numList:

print(k, end=", ")

print()

# ---------- MORE LIST FUNCTIONS ----------

numList = []

for i in range(5):

numList.append(random.randrange(1, 9))

# Sort a list

numList.sort()

# Reverse a list

numList.reverse()

for k in numList:

print(k, end=", ")

print()

# Insert value at index insert(index, value)

numList.insert(5, 10)

# Delete first occurrence of value

numList.remove(10)

for k in numList:

print(k, end=", ")

print()

# Remove item at index

numList.pop(2)

for k in numList:

print(k, end=", ")

print()

# ---------- LIST COMPREHENSIONS ----------

# You can construct lists in interesting ways using

# list comprehensions

# Perform an operation on each item in the list

# Create a list of even values

evenList = [i*2 for i in range(10)]

for k in evenList:

print(k, end=", ")

print()

# List of lists containing values to the power of

# 2, 3, 4

numList = [1,2,3,4,5]

listOfValues = [[math.pow(m, 2), math.pow(m, 3), math.pow(m, 4)]

for m in numList]

for k in listOfValues:

print(k)

print()

# Create a 10 x 10 list

multiDList = [[0] * 10 for i in range(10)]

# Change a value in the multidimensional list

multiDList[0][1] = 10

# Get the 2nd item in the 1st list

# It may help to think of it as the 2nd item in the 1st row

print(multiDList[0][1])

# Get the 2nd item in the 2nd list

print(multiDList[1][1])

# ---------- MULTIDIMENSIONAL LIST ----------

# Show how indexes work with a multidimensional list

listTable = [[0] * 10 for i in range(10)]

for i in range(10):

for j in range(10):

listTable[i][j] = "{} : {}".format(i, j)

for i in range(10):

for j in range(10):

print(listTable[i][j], end=" || ")

print()

# ---------- PROBLEM : CREATE MULTIPLICATION TABLE ----------

# With 2 for loops fill the cells in a multidimensional

# list with a multiplication table using values 1 - 9

'''

1, 2, 3, 4, 5, 6, 7, 8, 9,

2, 4, 6, 8, 10, 12, 14, 16, 18,

3, 6, 9, 12, 15, 18, 21, 24, 27,

4, 8, 12, 16, 20, 24, 28, 32, 36,

5, 10, 15, 20, 25, 30, 35, 40, 45,

6, 12, 18, 24, 30, 36, 42, 48, 54,

7, 14, 21, 28, 35, 42, 49, 56, 63,

8, 16, 24, 32, 40, 48, 56, 64, 72,

9, 18, 27, 36, 45, 54, 63, 72, 81

'''

# Create the multidimensional list

multTable = [[0] * 10 for i in range(10)]

# This will increment for each row

for i in range(1, 10):

# This will increment for each item in the row

for j in range(1, 10):

# Assign the value to the cell

multTable[i][j] = i * j

# Output the data in the same way you assigned it

for i in range(1, 10):

for j in range(1, 10):

print(multTable[i][j], end=", ")

print()

	Facebook
	YouTube
	Twitter
	LinkedIn

Learn to Program 6

Leave a Reply Cancel reply