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Replace values in list using Python [duplicate]
...oesn't actually save time:
items = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
for index, item in enumerate(items):
if not (item % 2):
items[index] = None
Here are (Python 3.6.3) timings demonstrating the non-timesave:
In [1]: %%timeit
...: items = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
......
What is the motivation for bringing Symbols to ES6?
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Most languages (all mainstream ones afaik) provide some mechanism, usually reflection, to get access to private anyway.
– Esailija
May 14 '14 at 10:58
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What is the difference between a schema and a table and a database?
... of which has the attributes defined by the schema. Tables might also have indexes on them to aid in looking up values on certain columns.
A database is, formally, any collection of data. In this context, the database would be a collection of tables. A DBMS (Database Management System) is the softw...
GroupBy pandas DataFrame and select most common value
...,'NY']})
source.groupby(['Country','City']).agg(lambda x:x.value_counts().index[0])
In case you are wondering about performing other agg functions in the .agg()
try this.
# Let's add a new col, account
source['account'] = [1,2,3,3]
source.groupby(['Country','City']).agg(mod = ('Short name', \...
Why does the month argument range from 0 to 11 in JavaScript's Date constructor?
...g., { "first", "second", "third", ..., "twenty-seventh", ... }) and try to index it by tm_mday. Then again, maybe they just saw the absolute utility in making off by one errors a regular occurrence.
– D.Shawley
Mar 31 '10 at 12:00
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Shiro vs. SpringSecurity [closed]
...y:http auto-config="true">
<security:form-login login-page="/index.do" authentication-failure-url="/index.do?login_error=1" default-target-url="/index.do"
always-use-default-target="true" />
<security:logout logout-success-url="/index.do" />
<sec...
How to drop columns by name in a data frame
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You should use either indexing or the subset function. For example :
R> df <- data.frame(x=1:5, y=2:6, z=3:7, u=4:8)
R> df
x y z u
1 1 2 3 4
2 2 3 4 5
3 3 4 5 6
4 4 5 6 7
5 5 6 7 8
Then you can use the which function and the - operat...
Creating a new column based on if-elif-else condition
...B'], 'C'] = 1
df.loc[df['A'] < df['B'], 'C'] = -1
Easy to solve using indexing. The first line of code reads like so, if column A is equal to column B then create and set column C equal to 0.
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How to maintain a Unique List in Java?
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A set is not a list, I cannot look up elements by index in a set in O(1) time (random access).
– wilmol
Sep 18 '19 at 1:32
add a comment
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Why there is no ForEach extension method on IEnumerable?
...e ForEach<> extension to be a little nicer than having to manage the index in a regular foreach myself:
public static int ForEach<T>(this IEnumerable<T> list, Action<int, T> action)
{
if (action == null) throw new ArgumentNullException("action");
var index = 0;
...