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Measuring elapsed time with the Time module
...
start_time = time.time()
# your code
elapsed_time = time.time() - start_time
You can also write simple decorator to simplify measurement of execution time of various functions:
import time
from functools import wraps
PROF_DATA...
using lodash .groupBy. how to add your own keys for grouped output?
...ame": "eddie",
"color": "green",
"age": "77"
}];
console.log(
_.chain(data)
// Group the elements of Array based on `color` property
.groupBy("color")
// `key` is group's name (color), `value` is the array of objects
.map((value, key) => ({ color: key, users: valu...
Purpose of Python's __repr__
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__repr__ should return a printable representation of the object, most likely one of the ways possible to create this object. See official documentation here. __repr__ is more for developers while __str__ is for end users.
A ...
Why can't (or doesn't) the compiler optimize a predictable addition loop into a multiplication?
...
It does now -- at least, clang does:
long long add_100k_signed(int *data, int arraySize)
{
long long sum = 0;
for (int c = 0; c < arraySize; ++c)
if (data[c] >= 128)
for (int i = 0; i < 100000; ++i)
sum += data[c];
re...
Auto layout constraints issue on iOS7 in UITableViewCell
...n the cell is reused like this:
For Static UITableViewController:
#ifdef __IPHONE_OS_VERSION_MIN_REQUIRED
#if __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_8_0
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [sup...
ZSH complains about RVM __rvm_cleanse_variables: function definition file not found
...
searched for "whats 'zcompdump' for" while diagnosing the __rvm_cleanse_variables issue... two birds, one search. +1's to everyone.
– max
Mar 21 '15 at 18:54
...
MongoDB sort排序、index索引教程 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...排列。
语法
sort()方法基本语法如下所示：
>db.COLLECTION_NAME.find().sort({KEY:1})
注意：
即使键值写错了（即文档中没有该键值），命令本身不会报错，当然排序也没有效果。
实例
col 集合中的数据如下：
{ "_id" : ObjectId("56066542...
What's the difference between utf8_general_ci and utf8_unicode_ci?
Between utf8_general_ci and utf8_unicode_ci , are there any differences in terms of performance?
8 Answers
...
Creating a dynamic choice field
...passing the user to the form init
class waypointForm(forms.Form):
def __init__(self, user, *args, **kwargs):
super(waypointForm, self).__init__(*args, **kwargs)
self.fields['waypoints'] = forms.ChoiceField(
choices=[(o.id, str(o)) for o in Waypoint.objects.filter(use...
Get IP address of visitors using Flask for Python
...est object and then get from this same Request object, the attribute remote_addr.
Code example
from flask import request
from flask import jsonify
@app.route("/get_my_ip", methods=["GET"])
def get_my_ip():
return jsonify({'ip': request.remote_addr}), 200
For more information see the Werkzeu...