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+--- Thread: about cmp fun (/thread-7474.html)
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about cmp fun - Sandesh - Jan-12-2018
why cmp() fun wll not work in python 3?
RE: about cmp fun - buran - Jan-12-2018
from Guido:
What’s New In Python 3.0, see the last bullet in Ordering Comparisons section
Quote:The cmp() function should be treated as gone, and the __cmp__() special method is no longer supported. Use __lt__() for sorting, __eq__() with __hash__(), and other rich comparisons as needed. (If you really need the cmp() functionality, you could use the expression (a > b) - (a < b) as the equivalent for cmp(a, b).)
RE: about Dictionary - Sandesh - Jan-12-2018
dict = {'Name': 'Zara', 'Age': 7}
print ("Value :" , dict.items())
if i run the above code i supposed to get= Value :([('Name', 'Zara'), ('Age', 7)]).
But i am getting it as=Value : dict_items([('Name', 'Zara'), ('Age', 7)])..
Help me out...
RE: about Dictionary - hshivaraj - Jan-12-2018
(Jan-12-2018, 10:29 AM)Sandesh Wrote: dict = {'Name': 'Zara', 'Age': 7}
print ("Value :" , dict.items())
if i run the above code i supposed to get= Value :([('Name', 'Zara'), ('Age', 7)]).
But i am getting it as=Value : dict_items([('Name', 'Zara'), ('Age', 7)])..
Help me out...
Firstly please use bbcode to wrap you code around. You have better chances of getting help, than one without it.
Quote:dict = {'Name': 'Zara', 'Age': 7} print ("Value :" , dict.items())if i run the above code i supposed to get=Value :([('Name', 'Zara'), ('Age', 7)]).
But i am getting it as=Value : dict_items([('Name', 'Zara'), ('Age', 7)])..
Help me out...
And I suspect that your getting this output
Value : dict_items([('Name', 'Zara'), ('Age', 7)]). Is because how the __repr__ magic method had been implemented for dict class in python3. In Python2 the output is what you expect. However this has changed in python>>> dict = {'Name': 'Zara', 'Age': 7}
>>> dict
{'Age': 7, 'Name': 'Zara'}
>>> dict.items()
[('Age', 7), ('Name', 'Zara')]
RE: about cmp fun - buran - Jan-12-2018
in python3
dict.items() method returns Dict View objects. In python2 same method will return list of 2-element tuples.So, you need to pass the dict view object to list() function in order to convert it to list (what you expect)
>>> d = {'a':1, 'b':2}
>>> d.items()
dict_items([('b', 2), ('a', 1)])
>>> list(d.items())
[('b', 2), ('a', 1)]However there is much serious problem in your code. Never use built-in functions as names, i.e. your dict name overwrite the built-in dict function:>>> my_dict = dict((('a',1), ('b',2)))
>>> my_dict
{'b': 2, 'a': 1}
>>> dict = {'Name': 'Zara', 'Age': 7}
>>> my_dict = dict((('a',1), ('b',2)))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'dict' object is not callable
RE: about cmp fun - Sandesh - Jan-23-2018
fo = open("foo.txt", "rw+")
print ("Name of the file: ", fo.name)
line = fo.readlines()
print ("Read Line: %s" % (line))
# Again set the pointer to the beginning
fo.seek(0, 0)
line = fo.readline()
print ("Read Line: %s" % (line))
# Close opened file
fo.close() If i run the above code I should get result as
Name of the file: foo.txt
Read Line: ['This is 1st line\n', 'This is 2nd line\n', 'This is 3rd line\n', 'This is 4th line\n', 'This is 5th line']
Read Line: This is 1st line
But i am getting something like
Name of the file: foo.txt
Read Line: []
Read Line:
Even though my txt file containing info....????
RE: about cmp fun - buran - Jan-23-2018
actually,
you are getting
Error:Traceback (most recent call last):
File "/home/***/***.py", line 2, in <module>
fo = open("foo.txt", "rw+")
ValueError: must have exactly one of create/read/write/append mode
>>> RE: about cmp fun - snippsat - Jan-23-2018
(Jan-23-2018, 06:22 AM)Sandesh Wrote: Even though my txt file containing info....????You are opening file for read and write,open for read
'r' which is the default mode.Here a better way with
with open and new string formatting f-string.with open('in.txt') as f:
contend = [i.strip() for i in f]
print(f'Name of file: {f.name}')
print(f'First line: {contend[0]}')
print(f'Read lines: {contend}')Output:Name of file: in.txt
First line: line 1
Read lines: ['line 1', 'line 2', 'line 3', 'line 4', 'line 5']RE: about cmp fun - Sandesh - Jan-26-2018
class Employee:
def _init_(self,first,last,pay):
self.first=first
self.last=last
self.pay=pay
self.number=number
emp1=Employee('corey','schafer',50000)
emp1=Employee('test','user',60000)
print(emp1.first)
print(emp1.last)
print(emp1.pay)when i try to run the above code it shows type Error saying that object() takes no parameter....!!!!!?????
RE: about cmp fun - snippsat - Jan-26-2018
Two underscore
__init__.Indentation is 4-space not tree.
class Employee:
def __init__(self, first, last, pay):
self.first = first
self.last = last
self.pay = pay
#self.number = number # Not used
emp1 = Employee('test', 'user', 60000)
print(emp1.first)
print(emp1.last)
print(emp1.pay)Output:test
user
60000