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Unable to cast object of type 'System.DBNull' to type 'System.String`
... even both. If the WHERE does not match any row, you'll get a null, if the selected row has NULL in that column, the return value is System.DBNull.
– Alexander
May 27 '14 at 7:52
...
What is fastest children() or find() in jQuery?
To select a child node in jQuery one can use children() but also find().
6 Answers
6
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How to downgrade or install an older version of Cocoapods
...e default version, so you have to sudo gem uninstall cocoapods first, then select 1.0.0 as the version to remove. Not sure if this has always been the behavior, but sudo gem install cocoapods -v 0.39.0 alone didn't do the trick for me once I had 1.0.0.
– fullofsquirrels
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Bash: Strip trailing linebreak from output
...ine character you want to remove, you can use 'head' from GNU coreutils to select everything except the last byte. This should be quite quick:
head -c -1 log.txt
Also, for completeness, you can quickly check where your newline (or other special) characters are in your file using 'cat' and the 'sh...
What's the right way to pass form element state to sibling/parent elements?
...ContextContainer = React.createContext(null);
const initialAppState = {
selected: "Nothing"
};
function App() {
// The app has a state variable and update handler
const [appState, updateAppState] = useState(initialAppState);
return (
<div>
<h1>Passing state between c...
Submitting a form by pressing enter without a submit button
...
A keypress is also triggered for a selection from autocomplete, i.e. if the user is inputting an email address and he/she selects a previously given one from the browser's autocomplete by hitting enter, then your form will submit. Not what your users will expe...
How to get a dependency tree for an artifact?
...ent version of m2eclipse (which you should if you use eclipse and maven):
Select the menu entry
Navigate -> Open Maven POM
and enter the artifact you are looking for.
The pom will open in the pom editor, from which you can select the tab Dependency Hierarchy to view the dependency hierarchy (...
SVN command to delete all locally missing files
...TortoiseSVN, just do a Check for Modifications, sort by the Status column, select all the entries marked missing, right-click to open the context menu, and select Delete. Finally, commit to publish the changes to the repository.
If you are on Windows, but prefer the command-line and enjoy dabbling ...
Inserting a Python datetime.datetime object into MySQL
...
when iserting into t-sql
this fails:
select CONVERT(datetime,'2019-09-13 09:04:35.823312',21)
this works:
select CONVERT(datetime,'2019-09-13 09:04:35.823',21)
easy way:
regexp = re.compile(r'\.(\d{6})')
def to_splunk_iso(dt):
"""Converts the datetime ...
Finding ALL duplicate rows, including “elements with smaller subscripts”
...gt;% filter(n > 1) # data frame
df %>% add_count(col1, col2) %>% select(n) > 1 # logical vector
For duplicate rows (considering all columns):
df %>% group_by_all %>% add_tally %>% ungroup %>% filter(n > 1)
df %>% group_by_all %>% add_tally %>% ungroup %>% ...