Chapter 10/11
does the brackets mean row or columns in matrix
rows
how to combine lists?
s1+s2
how to split a string into a list?
string.split()
Assume m = [[1, 2], [3, 4], [5, 6]], what is len(m)
3
"Welcome to Python".split() is
["Welcome", "to", "Python"]
what is list("abcd")
["a","b","c","d"]
suppose list1=[2*x for x in range(0,4)] list1 is?
[0,2,4,6]
Suppose list1 is [3, 4, 5, 20, 5, 25, 1, 3], what is list1 after list1.sort()?
[1, 3, 3, 4, 5, 5, 20, 25]
suppose list1 is [1,3,2,4,5,2,1,0] which is correct a. print(list1[0]) b. print(list1[:2]) c. print(list1[:-2]) d. print(list1[4:9])
a. CORRECT b. CORRECT c. CORRECT d.FALSE out of range
list1[11,2,23] and list2=[2,11,23] list1==list2??
false
alternate way using for loop in list?
for u in myList:
how to find row with greatest sum?
have a for loop to go through the rows an find sum using sum(matrix[rowNum])
how to shuffle values in a list?
import randome random.shuffle(nameOfList)
how to find column len in matrix?
len(matrix[row])
how to find length, minimum, maximum,sum of a list?
len(nameOfString) min(nameOfString) max(nameOfString) sum(nameOfString) #only works for int
how to remove a certain object from a list and return the object? what if you dont want it to return anything
list.pop(i) list1.remove(object)
all the different ways to create a list?
list1 = list() list1 = [] list1= list([2,3,4,5]) list1 = [12,4,5] list1 = list(range(3,6)) list1 = ("abcd") CAN BE OF MIXED TYPES
two ways to duplicate a list?
list2=[x for x in list1] list2=[]+list1
how to use +/* operators in lists?
list3= list1 + list2 list4 = 3*list1 will repeat values in list1 3 times
How to add a value to list?
listName.append()
how to only get a certain section of a list?
listName[i:j] #j not included
how to find how many times a certain appears in list?
nameOfList.count(x:object)-->returns int
how to add list of value to another list
nameOfList.extend(l:list)
how to find the index of the first occurrence of a value?
nameOfList.index(x:object)--> returns int
how to insert a certain element at a certain index instead of the end of list?
nameOflist.insert(index, object)
how do you shuffle list1?
random.shuffle(list1)
how to reverse a list and arrange it order?
.reverse() .sort()
myList = [1, 5, 5, 5, 5, 1] max = myList[0] indexOfMax = 0 for i in range(1, len(myList)): if myList[i] > max: max = myList[i] indexOfMax = i print(indexOfMax)
1
What will be displayed by the following code? myList = [1, 2, 3, 4, 5, 6] for i in range(0, 5): myList[i + 1] = myList[i]f or i in range(0, 6): print(myList[i], end = " ")
1 1 1 1 1 1
list comprehensions for creating 1.list1 with 0.5* all value in list2 2.list1 with values in list if they are less than 1.5
1.list1 = [0.5*x for x in list2] 2.list1 = [x for x in list2 if x<1.5]
Assume m = [[1, 2], [3, 4], [5, 6]], what is len(m[0])
2
What will be displayed by the following code? m = [[1, 2], [3, 4], [5, 6]] print(m[0][1])
2
list1 is [3,4,5,20,5,25,1,3] what is list1.index(5)?
2
what is max(list1)? list1 is [3,4,5,20,5,25,1,3]
25
what happens when you try to access an index which is not in list?
RunTime IndexError
how to access values in a list?
using negative and positive values
how to find if a value is or not in the list?
x in s x not in s