Can we use elif in list comprehension? Example : l = [1, 2, 3, 4, 5] for values in l: if values==1: print ‘yes’ elif values==2: print ‘no’ else: print ‘idle’ Can we include the elif in our list comprehension, in a similar fashion to the code above? For example, an answer like: [‘yes’, ‘no’, … Read more
I am trying to create a dictionary from a csv file. The first column of the csv file contains unique keys and the second column contains values. Each row of the csv file represents a unique key, value pair within the dictionary. I tried to use the csv.DictReader and csv.DictWriter classes, but I could only … Read more
In terms of performance in Python, is a list-comprehension, or functions like map(), filter() and reduce() faster than a for loop? Why, technically, they run in a C speed, while the for loop runs in the python virtual machine speed?. Suppose that in a game that I’m developing I need to draw complex and huge … Read more
How do you access other class variables from a list comprehension within the class definition? The following works in Python 2 but fails in Python 3: class Foo: x = 5 y = [x for i in range(1)] Python 3.2 gives the error: NameError: global name ‘x’ is not defined Trying Foo.x doesn’t work either. … Read more
It’s more about python list comprehension syntax. I’ve got a list comprehension that produces list of odd numbers of a given range: [x for x in range(1, 10) if x % 2] This makes a filter – I’ve got a source list, where I remove even numbers (if x % 2). I’d like to use … Read more
Having an iterator object, is there something faster, better or more correct than a list comprehension to get a list of the objects returned by the iterator? user_list = [user for user in user_iterator] 3 Answers 3
This question already has answers here: if/else in a list comprehension (12 answers) Closed 3 years ago. Here is the code I was trying to turn into a list comprehension: table=”” for index in xrange(256): if index in ords_to_keep: table += chr(index) else: table += replace_with Is there a way to add the else statement … Read more
This question already has answers here: Closed 9 years ago. Possible Duplicate: A Transpose/Unzip Function in Python I have a list of tuples, where I want to unzip this list into two independent lists. I’m looking for some standardized operation in Python. >>> l = [(1,2), (3,4), (8,9)] >>> f_xxx (l) [ [1, 3, 8], … Read more
I have a list of variable length and am trying to find a way to test if the list item currently being evaluated is the longest string contained in the list. And I am using Python 2.6.1 For example: mylist = [‘abc’,’abcdef’,’abcd’] for each in mylist: if condition1: do_something() elif ___________________: #else if each is … Read more
I have this nested list: l = [[’40’, ’20’, ’10’, ’30’], [’20’, ’20’, ’20’, ’20’, ’20’, ’30’, ’20’], [’30’, ’20’, ’30’, ’50’, ’10’, ’30’, ’20’, ’20’, ’20’], [‘100’, ‘100’], [‘100’, ‘100’, ‘100’, ‘100’, ‘100’], [‘100’, ‘100’, ‘100’, ‘100’]] Now, what I want to do is convert each element in a list to float. My solution … Read more
