Another question asked specifically how to perform multiple left joins using dplyr in R . The question was marked as a duplicate of this one so I answer here, using the 3 sample data frames below: x <- data.frame(i = c(“a”,”b”,”c”), j = 1:3, stringsAsFactors=FALSE) y <- data.frame(i = c(“b”,”c”,”d”), k = 4:6, stringsAsFactors=FALSE) z … Read more
Here’s a full listing of a program and its results. The code: using System; namespace TimeZoneIds { class Program { static void Main(string[] args) { foreach (TimeZoneInfo z in TimeZoneInfo.GetSystemTimeZones()) { // For a Console App Console.WriteLine(z.Id + “,” + z.BaseUtcOffset + “,” + z.StandardName + “,” + z.DisplayName + “,” + z.DaylightName); // For … Read more
Use df.to_dict(‘records’) — gives the output without having to transpose externally. In [2]: df.to_dict(‘records’) Out[2]: [{‘customer’: 1L, ‘item1’: ‘apple’, ‘item2’: ‘milk’, ‘item3’: ‘tomato’}, {‘customer’: 2L, ‘item1’: ‘water’, ‘item2’: ‘orange’, ‘item3’: ‘potato’}, {‘customer’: 3L, ‘item1’: ‘juice’, ‘item2’: ‘mango’, ‘item3’: ‘chips’}]
You can use operator.itemgetter: from operator import itemgetter a = [-2, 1, 5, 3, 8, 5, 6] b = [1, 2, 5] print(itemgetter(*b)(a)) # Result: (1, 5, 5) Or you can use numpy: import numpy as np a = np.array([-2, 1, 5, 3, 8, 5, 6]) b = [1, 2, 5] print(list(a[b])) # Result: [1, … Read more
Save yourself some pain… using System.Linq; int[] ints = new [] { 10, 20, 10, 34, 113 }; List<int> lst = ints.OfType<int>().ToList(); // this isn’t going to be fast. Can also just… List<int> lst = new List<int> { 10, 20, 10, 34, 113 }; or… List<int> lst = new List<int>(); lst.Add(10); lst.Add(20); lst.Add(10); lst.Add(34); lst.Add(113); … Read more
You could use a list comprehension or a generator expression instead: ‘, ‘.join([str(x) for x in list]) # list comprehension ‘, ‘.join(str(x) for x in list) # generator expression
You can use the LINQ Concat and ToList methods: var allProducts = productCollection1.Concat(productCollection2) .Concat(productCollection3) .ToList(); Note that there are more efficient ways to do this – the above will basically loop through all the entries, creating a dynamically sized buffer. As you can predict the size to start with, you don’t need this dynamic sizing… … Read more
A collections.deque is optimized for pulling and pushing on both ends. They even have a dedicated rotate() method. from collections import deque items = deque([1, 2]) items.append(3) # deque == [1, 2, 3] items.rotate(1) # The deque is now: [3, 1, 2] items.rotate(-1) # Returns deque to original state: [1, 2, 3] item = items.popleft() … Read more
[float(i) for i in lst] to be precise, it creates a new list with float values. Unlike the map approach it will work in py3k.
You are looking for the command scandir. $path=”/tmp”; $files = scandir($path); Following code will remove . and .. from the returned array from scandir: $files = array_diff(scandir($path), array(‘.’, ‘..’));