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Convert array of integers to comma-separated string
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I am using .NET 4.5. I tried to concat the comma separated numbers with a string. I got an error saying "cannot convert string[] to char". So the earlier version worked flawlessly.
– Prasanth G
Jan 30 at 12:49
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How do I append one string to another in Python?
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If you only have one reference to a string and you concatenate another string to the end, CPython now special cases this and tries to extend the string in place.
The end result is that the operation is amortized O(n).
e.g.
s = ""
for i in range(n):
s+=str(i)
used to ...
Transposing a 2D-array in JavaScript
...rix.reduce((prev, next) => next.map((item, i) =>
(prev[i] || []).concat(next[i])
), []);
}
Lodash/Underscore by marcel
function tranpose(matrix) {
return _.zip(...matrix);
}
// Without spread operator.
function transpose(matrix) {
return _.zip.apply(_, [[1,2,3], [1,2,3], [1,2,3]]...
How do I create a PDO parameterized query with a LIKE statement?
...e LIKE with % partial matching for MySQL databases: WHERE column_name LIKE CONCAT('%', :dangerousstring, '%')
where the named parameter is :dangerousstring.
In other words, use explicitly unescaped % signs in your own query that are separated and definitely not the user input.
Edit: Concatenati...
Creating an empty Pandas DataFrame, then filling it?
...ire handling the index appropriately).
Things you should NOT do
append or concat inside a loop
Here is the biggest mistake I've seen from beginners:
df = pd.DataFrame(columns=['A', 'B', 'C'])
for a, b, c in some_function_that_yields_data():
df = df.append({'A': i, 'B': b, 'C': c}, ignore_index=...
When to use StringBuilder in Java [duplicate]
...is supposed to be generally preferable to use a StringBuilder for string concatenation in Java. Is this always the case?
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erb, haml or slim: which one do you suggest? And why? [closed]
...s in smaller screens
visually cleaner structure
has built in helpers (haml_concat, haml_capture) to utilize haml in helper methods
class chaining
lots of useful syntactic sugar like # for divs or . for class chaining, or :javascript for JS tags
Cons
whitespace dependent which makes for some har...
How does the String class override the + operator?
...ls of the string conversion context.
15.18.1.
Optimization of String Concatenation :
An implementation may choose to perform conversion and concatenation
in one step to avoid creating and then discarding an intermediate
String object. To increase the performance of repeated string
conc...
Return multiple columns from pandas apply()
... series, new columns exist):')
df_test = create_new_df_test()
df_test = pd.concat([df_test, pd.DataFrame(columns=['size_kb', 'size_mb', 'size_gb'])])
%timeit result = df_test.apply(sizes_pass_series_return_series, axis=1)
print('\nPandafied (pass series, return tuple, new columns dont exist):')
df_...
Insert a row to pandas dataframe
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Not sure how you were calling concat() but it should work as long as both objects are of the same type. Maybe the issue is that you need to cast your second vector to a dataframe? Using the df that you defined the following works for me:
df2 = pd.DataFra...