Python Programming Basics Day#3
Day3
It is Day#3 of Linux World Python Training.
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Passing a Tuple to Function
>>> def mysum(x):
... print(x)
...
>>> mysum(5)
5
>>> mysum(5,6,7,8)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: mysum() takes 1 positional argument but 4 were given
>>> def mysum(*x):
... print(x)
...
>>> mysum(5,6,7,8)
(5, 6, 7, 8)
>>> mysum(5)
(5,)
>>>
Passing a variable size tuple and perform some action on the data
>>> def mysum(*data):
... j=0
... for i in data:
... j+=i
... return j
...
>>> mysum(5,6,7,8)
26
>>> mysum(5,6,7,8,9)
35
>>> mysum(5)
5
>>>
What if we pass a list as parameter?
>>> mysum([5,6,7,8,9])
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 4, in mysum
TypeError: unsupported operand type(s) for +=: 'int' and 'list'
>>>
j is an integer and i is a list, so adding them together caused the TypeError.
To fix this, just add a * before the list data while passing.
>>> mysum(*[5,6,7,8,9])
35
>>> mysum(*[5,6,7,8,9.12])
35.12
>>> mysum(*[5,6,7,8,9,12])
47
>>>
All Conditions
>>> math=49
>>> phy=40
>>> econ=67
>>> chem=56
>>> school_condition=[ math >50, econ>50, phy>45, chem>50]
>>> school_condition
[False, True, False, True]
>>> type(school_condition)
<class 'list'>
>>>
>>> all(school_condition)
False
>>>
Lets change the values to make all conditions True
>>> school_condition=[ math >40, econ>30, phy>25, chem>50] # List of conditions
>>> school_condition
[True, True, True, True]
>>> all(school_condition)
True
>>>
>>> if all(school_condition):
... print("pass")
... else:
... print("fail")
...
pass
>>>
>>> 5 >3 and 7>2
True
>>> 5 >3 and 7>9
False
>>> 5 >9 and 7>9
False
>>> 5 >9 or 7>9
False
>>> 5 >9 or 7>3
True
>>>
Any Condition
>>> school_condition=[ math >40, econ>30, phy>55, chem>50]
>>> school_condition
[True, True, False, True]
>>> any(school_condition)
True
>>>
Nested Lists
Multi-dimensional lists
>>> day1=[45,34,45,23]
>>> day2=[34,45,23,45]
>>> month1=[day1,day2]
>>> type(month1)
<class 'list'>
>>> type(day1)
<class 'list'>
>>> month1
[[45, 34, 45, 23], [34, 45, 23, 45]]
>>>
>>> month1[0]
[45, 34, 45, 23]
>>> month1[1]
[34, 45, 23, 45]
>>>
>>> month1[1][0]
34
>>> month1[1][1]
45
>>> month1[1][2]
23
>>> month1[1][3]
45
>>> month1[1][2:]
[23, 45]
>>>
>>> month1
[[45, 34, 45, 23], [34, 45, 23, 45]]
>>> dir(month1)
['__add__', '__class__', '__class_getitem__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']
>>>
In list, getting a column from each row is possible with numpy aray.
Numpy
>>> import numpy
>>>
>>> numpy.array(month1)
array([[45, 34, 45, 23],
[34, 45, 23, 45]])
>>> final_month=numpy.array(month1)
>>> month1
[[45, 34, 45, 23], [34, 45, 23, 45]]
>>> final_month
array([[45, 34, 45, 23],
[34, 45, 23, 45]])
>>> type(final_month)
<class 'numpy.ndarray'>
>>> dir(final_month)
['T', '__abs__', '__add__', '__and__', '__array__', '__array_finalize__', '__array_function__', '__array_interface__', '__array_prepare__', '__array_priority__', '__array_struct__', '__array_ufunc__', '__array_wrap__', '__bool__', '__class__', '__complex__', '__contains__', '__copy__', '__deepcopy__', '__delattr__', '__delitem__', '__dir__', '__divmod__', '__doc__', '__eq__', '__float__', '__floordiv__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__iadd__', '__iand__', '__ifloordiv__', '__ilshift__', '__imatmul__', '__imod__', '__imul__', '__index__', '__init__', '__init_subclass__', '__int__', '__invert__', '__ior__', '__ipow__', '__irshift__', '__isub__', '__iter__', '__itruediv__', '__ixor__', '__le__', '__len__', '__lshift__', '__lt__', '__matmul__', '__mod__', '__mul__', '__ne__', '__neg__', '__new__', '__or__', '__pos__', '__pow__', '__radd__', '__rand__', '__rdivmod__', '__reduce__', '__reduce_ex__', '__repr__', '__rfloordiv__', '__rlshift__', '__rmatmul__', '__rmod__', '__rmul__', '__ror__', '__rpow__', '__rrshift__', '__rshift__', '__rsub__', '__rtruediv__', '__rxor__', '__setattr__', '__setitem__', '__setstate__', '__sizeof__', '__str__', '__sub__', '__subclasshook__', '__truediv__', '__xor__', 'all', 'any', 'argmax', 'argmin', 'argpartition', 'argsort', 'astype', 'base', 'byteswap', 'choose', 'clip', 'compress', 'conj', 'conjugate', 'copy', 'ctypes', 'cumprod', 'cumsum', 'data', 'diagonal', 'dot', 'dtype', 'dump', 'dumps', 'fill', 'flags', 'flat', 'flatten', 'getfield', 'imag', 'item', 'itemset', 'itemsize', 'max', 'mean', 'min', 'nbytes', 'ndim', 'newbyteorder', 'nonzero', 'partition', 'prod', 'ptp', 'put', 'ravel', 'real', 'repeat', 'reshape', 'resize', 'round', 'searchsorted', 'setfield', 'setflags', 'shape', 'size', 'sort', 'squeeze', 'std', 'strides', 'sum', 'swapaxes', 'take', 'tobytes', 'tofile', 'tolist', 'tostring', 'trace', 'transpose', 'var', 'view']
>>> final_month
array([[45, 34, 45, 23],
[34, 45, 23, 45]])
>>> final_month[1]
array([34, 45, 23, 45])
>>> final_month[2]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
IndexError: index 2 is out of bounds for axis 0 with size 2
>>> final_month[0]
array([45, 34, 45, 23])
>>> final_month[:]
array([[45, 34, 45, 23],
[34, 45, 23, 45]])
>>> final_month[:,2]
array([45, 23])
>>> final_month[:,1]
array([34, 45])
>>> final_month[:,2]
array([45, 23])
>>> final_month[:,3]
array([23, 45])
>>> final_month[:,4]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
IndexError: index 4 is out of bounds for axis 1 with size 4
>>> final_month[:,0]
array([45, 34])
>>> final_month[:,1:3]
array([[34, 45],
[45, 23]])
>>> final_month
array([[45, 34, 45, 23],
[34, 45, 23, 45]])
>>>
>>> final_month[1,1:3]
array([45, 23])
>>> final_month[0,1:3]
array([34, 45])
>>>
Vector is a one-dimensional array.
Matrix is a two-dimensional array.
If Else
Python supports Comparison Chain.
>>> exp=5
>>> if exp>2 and exp<10:
... print("Offer")
... else:
... print("No")
...
Offer
>>> if 2 < exp <10: ## Alternate and simple condition
... print("Offer")
... else:
... print("No")
...
Offer
>>>
