Consulting - Quality
Difference makes the DIFFERENCE
ERROR HANDLING & LISTS
from PadhAI Class
Exception Handling¶
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def input_single_float(prompt):
user_input = input(prompt)
output = float(user_input)
return output
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input_single_float('Enter the value of PI')
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def input_single_float_01(prompt):
user_input = input(prompt)
try:
output = float(user_input)
except ValueError:
print("Input value is not as expected - enter numeric value")
output = None
except UnboundLocalError:
output = None
return output
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input_single_float_01("Enter any number")
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Lists¶
- List is a compound datatype, meaning, it can contain any datatype in the same contaner.
- Lists are indicated by [ ] square braces
- to access individual items, we use the index of the item, index starts from 0
- to get group of items we use : as seperator eg: word[
: ] is inclusive and is exclusive. - to get the last item, use index as -1
- like wise, to get items in reverse order, use -2, -3 etc...
- expressions can be used with lists. for example, lst[1] + 10 returns item in 2nd index + 10
- len() is used to get the length of the list
- Lists are mutable, meaning, they can be changed, appended, deleted, added, inserted and the others
- Individual items in the list of lists need not be the same, ie., list(list[1]) need not be the same as list(list[2])
- if there exists two lists A and B, and if B is assigned to A like B = A, then, changing element in list A will also be changed in list B, because, both the lists A and B point to the same data - if needed to keep A and B to be mutually independent, then copy list A to B
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course = "Foundations of Data Science"
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words = course.split()
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print(words)
# content within a square bracket is a list type
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words[1]
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words[0]
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words[1:3]
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words[2:5]
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words[3:34]
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print(type(words))
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print(words[0])
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print(words[-1])
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print(words[-2])
List with integers - Fibonacci Series¶
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fibo_list = [1,1,2,3,5,8,13,21,34]
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print(type(fibo_list))
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print(fibo_list[2])
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print(fibo_list[2] + 10)
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print(fibo_list[2:4])
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print(type(fibo_list[3:6]))
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print(fibo_list[3:6])
printing list of items in the list - fibo_list¶
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for i in fibo_list:
print(i)
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print(len(fibo_list))
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length = len(fibo_list)
for i in range(length):
print(i)
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for i in range(length):
print(i + 1.52)
List with multiple data types¶
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bm_record = ['Abel', 12, 23.34, False]
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print(type(bm_record))
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print(bm_record[2])
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print(bm_record[1])
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print(bm_record[1:3])
working with lists¶
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bm_record.append('abel@idontknow.com')
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bm_record
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print(bm_record)
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for i in bm_record:
print(i, type(i))
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bm_record[0] = "Abel Ashwin"
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for i in bm_record:
print(i)
count returns the number of times, the given item is repeated in the list¶
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bm_record.count("Abel Ashwin")
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bm_record.extend?
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cm_record = ['Sameer', 25.254, 12.23]
with APPEND, new list becomes another list in the existing list, ie., list within a list¶
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bm_record.append(cm_record)
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bm_record
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print(bm_record)
with EXTEND, the new list contents are added to the existing list¶
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bm_record.extend(cm_record)
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print(bm_record)
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bm_record = ['Abel', 12, 23.34, False]
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print(bm_record.reverse())
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print(bm_record)
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print(fibo_list.reverse())
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fibo_list.reverse()
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print(fibo_list)
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fibo_list.sort()
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print(fibo_list.sort())
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fibo_list.remove?
# Remove first occurrence of value.
#Raises ValueError if the value is not present.
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fibo_list.pop?
# Remove and return item at index (default last).
# Raises IndexError if list is empty or index is out of range.
Lists Continued¶
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bm_record = [
['Abel', 75, 1.73, False],
['Ashwin', 120, 1.78, True]
]
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print(type(bm_record))
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bm_record
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bm_record[0]
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bm_record[1]
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bm_record[0][1]
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bm_record[1][2]
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bm_record[0][0] = "Abel brother of Cain"
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bm_record[0]
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bm_record[0].append("abel@idontknow.com")
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bm_record[0]
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bm_record
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bm_record[1][1] = 125
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bm_record
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identity_3 = [
[1,0,0],
[0,1,0],
[0,0,1]
]
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identity_3[1][2]
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identity_3[1][1]
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identity_3[1, 0]
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A = [1, 2]
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B = A
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A[0] = A[0] + A[1]
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print(A)
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print(B)
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A = [1, 2]
Copy contents of list A to list B so that when assigned B to A, the values doesnt change¶
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B = [item for item in A]
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print(B)
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A[0] = A[0] + A[1]
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print(A)
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print(B)
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A = [
[1, 1],
[1, 0]
]
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!pip install nbconvert
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%shell jupyter nbconvert --to html /content/testfile.ipynb
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# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ END CELL ~~~~~~~~~~~~~~~~~~~~~~~~~~~~