loops

问题 I have a script that loops through a series of four (or less) characters strings. For example: aaaa aaab aaac aaad If have been able to implement it with nested for loops like so: chars = string.digits + string.uppercase + string.lowercase for a in chars: print '%s' % a for b in chars: print '%s%s' % (a, b) for c in chars: print '%s%s%s' % (a, b, c) for d in chars: print '%s%s%s%s' % (a, b, c, d) Is this sort of loop nesting a bad thing, and if so, what would be a better way of accomplishing

问题 I have a script that loops through a series of four (or less) characters strings. For example: aaaa aaab aaac aaad If have been able to implement it with nested for loops like so: chars = string.digits + string.uppercase + string.lowercase for a in chars: print '%s' % a for b in chars: print '%s%s' % (a, b) for c in chars: print '%s%s%s' % (a, b, c) for d in chars: print '%s%s%s%s' % (a, b, c, d) Is this sort of loop nesting a bad thing, and if so, what would be a better way of accomplishing

问题 New to Python, trying to understand how this iterative loop that is intended to remove all items form the list is handling the indexes in the list and why it stops where it does... Why does this loop: foo = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'] for i in foo: foo.remove(i) print foo Stop here? ['b', 'd', 'f', 'h'] Instead of here? ['H'] Also, what's happening "under the hood" with the indexes here? With every iteration, is Python keeping track of which index is next while at the same time,

问题 I can't. I know. Shopify imposes a limit when it comes to the number of products one can loop through on a page. The current limit is 50. Actually, this is not true . One can loop through all the products of a store using liquid : {% paginate collections["all-products"].products by 10000 %} {% for product in collections["all-products"].products %} {% comment %}looping through all 10000 products{% endcomment %} {% endfor %} {% endpaginate %} In the above example, if a store has up to 10000

问题 I can't. I know. Shopify imposes a limit when it comes to the number of products one can loop through on a page. The current limit is 50. Actually, this is not true . One can loop through all the products of a store using liquid : {% paginate collections["all-products"].products by 10000 %} {% for product in collections["all-products"].products %} {% comment %}looping through all 10000 products{% endcomment %} {% endfor %} {% endpaginate %} In the above example, if a store has up to 10000

问题 I want to create a loop who has this sense: for i in xrange(0,10): for k in xrange(0,10): z=k+i print z where the output should be 0 2 4 6 8 10 12 14 16 18 回答1: You can use zip to turn multiple lists (or iterables) into pairwise* tuples: >>> for a,b in zip(xrange(10), xrange(10)): ... print a+b ... 0 2 4 6 8 10 12 14 16 18 But zip will not scale as well as izip (that sth mentioned) on larger sets. zip 's advantage is that it is a built-in and you don't have to import itertools -- and whether

问题 Perhaps it is not good programming practice, but is it possible to define a for loop macro? For example, #define loop(n) for(int ii = 0; ii < n; ++ ii) works perfectly well, but does not give you the ability to change the variable name ii . It can be used: loop(5) { cout << "hi" << " " << "the value of ii is:" << " " << ii << endl; } But there is no choice of the name/symbol ii . Is it possible to do something like this? loop(symbol_name, n) where the programmer inserts a symbol name into "

问题 I'd like to create five subplots (one for each category in a specific column of a dataframe) on a seaborn histogram (distplot). My dataset is: prog score cool 1.9 cool 3.7 yay 4.5 yay 2.6 neat 1.4 neat 7 neat 6 wow 4.1 wow 1.7 wow 1.4 hooray 6.6 hooray 5.6 hooray 4.9 yikes 1.2 yikes 3.9 yikes 6.9 I don't want all of the 'prog's plotted, just each in a list: prog_list = ['cool', 'yay', 'neat', 'yikes', 'wow'] scores = df['score'] f, axes = plt.subplots(3, 2, figsize=(15, 15)) # Delete last

问题 I'd like to create five subplots (one for each category in a specific column of a dataframe) on a seaborn histogram (distplot). My dataset is: prog score cool 1.9 cool 3.7 yay 4.5 yay 2.6 neat 1.4 neat 7 neat 6 wow 4.1 wow 1.7 wow 1.4 hooray 6.6 hooray 5.6 hooray 4.9 yikes 1.2 yikes 3.9 yikes 6.9 I don't want all of the 'prog's plotted, just each in a list: prog_list = ['cool', 'yay', 'neat', 'yikes', 'wow'] scores = df['score'] f, axes = plt.subplots(3, 2, figsize=(15, 15)) # Delete last

问题 Here's the question I've been given: Create a 4X3 integer array and fill it, column by column using loops, with the odd numbers starting with 1. In a separate, one dimensional array, store the average of each column of the 4X3 array. Output the 4X3 array (as a 4X3 array) and output the average of each column underneath each column. Label these as the average. I just learned that I can make an array like this: N[4][3] , but should I even do that here? I feel like setting up an array for each