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Selecting multiple columns in a pandas dataframe
...ou can just return a view of only those columns by passing a list into the __getitem__ syntax (the []'s).
df1 = df[['a', 'b']]
Alternatively, if it matters to index them numerically and not by their name (say your code should automatically do this without knowing the names of the first two columns)...
How to drop unique in MySQL?
...te the foreign key afterwards. e.g ALTER TABLE fuinfo DROP foreign key fk_name_for_email;
– Brad Parks
Dec 12 '12 at 20:08
...
How do I pass JavaScript variables to PHP?
...;?php
$query = "SELECT * FROM salarie";
$result = mysql_query($query);
if ($result) :
?>
<select id="salarieids" name="salarieid">
<?php
while ($row = mysql_fetch_assoc($result)) {
echo '<option value="'...
Unable to locate tools.jar
...
Add JAVA_HOME and the /bin directory to your path. You realize that this answer is two years old, right?
– duffymo
Jul 23 '13 at 12:52
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Iterating C++ vector from the end to the beginning
...
The best way is:
for (vector<my_class>::reverse_iterator i = my_vector.rbegin();
i != my_vector.rend(); ++i ) {
}
rbegin()/rend() were especially designed for that purpose. (And yes, incrementing a reverse_interator moves it backward.)
Now...
Best way to generate random file names in Python
...me
basename = "mylogfile"
suffix = datetime.datetime.now().strftime("%y%m%d_%H%M%S")
filename = "_".join([basename, suffix]) # e.g. 'mylogfile_120508_171442'
share
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Unix - create path of folders and file
...or the code example can be: mkdir -p /my/other/path/here && touch $_/cpredthing.txt. The $_ expands to essentially the "last argument in the last command executed".
– Sgnl
Apr 19 '16 at 1:37
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服务卡片（ServiceWidget）使用指导 · App Inventor 2 中文网
...，将同名事件的处理合并到一个事件积木中。
when 按钮_登记.Click() {
ServiceWidget1.RegisterFormId(文本输入框_卡片编号.Text)
ServiceWidget1.UpdateWidget(文本输入框_卡片数据.Text)
}
when ServiceWidget1.WidgetUpdated(卡片ID) {
标签1.Text = join("已更...
iReport not starting using JRE 8
...ice the jre-7u67-windows-x64.tar.gz you end up with a folder named jre1.7.0_67. Put that folder in the iReport-5.6.0 directory:
and then go into the etc folder and edit the file ireport.conf and add the following line into it:
For Windows
jdkhome=".\jre1.7.0_67"
For Linux
jdkhome="./jre1.7.0_67...
How to check if AlarmManager already has an alarm set?
... a pending intent like this:
Intent intent = new Intent("com.my.package.MY_UNIQUE_ACTION");
PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0,
intent, PendingIntent.FLAG_UPDATE_CURRENT);
Calendar calendar = Calendar.getInstance();
calendar.se...