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How do I put a variable inside a string?
...of embedding a single number in a string, I needed to generate a series of file names of the form 'file1.pdf', 'file2.pdf' etc. This is how it worked:
['file' + str(i) + '.pdf' for i in range(1,4)]
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Java - JPA - @Version annotation
...operty:
@Entity
public class MyEntity implements Serializable {
@Id
@GeneratedValue
private Long id;
private String name;
@Version
private Long version;
//...
}
On update, the field annotated with @Version will be incremented and added to the WHERE clause, some...
Remove rows with all or some NAs (missing values) in data.frame
...
tidyr has a new function drop_na:
library(tidyr)
df %>% drop_na()
# gene hsap mmul mmus rnor cfam
# 2 ENSG00000199674 0 2 2 2 2
# 6 ENSG00000221312 0 1 2 3 2
df %>% drop_na(rn...
Remove last item from array
...n.js"></script>
<b>Original Array : </b>
<div id="div1"></div>
<br/>
<b>After slice(0, -1): </b>
<div id="div2"></div>
instead of doing :
arr.slice(-1); // returns [2]
Here is a demo:
var arr = [1, 0, 2];
var ne...
Solving a “communications link failure” with JDBC and MySQL [duplicate]
...that you need to change the MySQL settings, you can refer to the following files:
Linux: /etc/mysql/my.cnf or /etc/my.cnf (depending on the Linux distribution and MySQL package used)
Windows: C:**ProgramData**\MySQL\MySQL Server 5.6\my.ini (Notice it's ProgramData, not Program Files)
Here are th...
what exactly is device pixel ratio?
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thanx, so if i make a css file for iphone 4 and give the page CSS measurements of 480 x 320 and width=device-width i'll have it stretched to full screen?
– ilyo
Jan 9 '12 at 8:44
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What exactly is a Context in Java? [duplicate]
...ic void main(String[] args) throws IOException { // (1)
File file = new File("D:/text.txt");
String text = "";
BufferedReader reader = new BufferedReader(new FileReader(file));
String line;
while ((line = reader.readLine()) != null){ // (2)
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How to validate IP address in Python? [duplicate]
....inet_aton("2001:660::1") Traceback (most recent call last): File "<stdin>", line 1, in <module> socket.error: illegal IP address string passed to inet_aton
– bortzmeyer
Dec 1 '08 at 10:53
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What is the difference between “INNER JOIN” and “OUTER JOIN”?
...ally show any distinction between different types of join predicate or provide a framework for reasoning about how they will operate.
There is no substitute for understanding the logical processing and it is relatively straightforward to grasp anyway.
Imagine a cross join.
Evaluate the on clause ag...
How do I debug an MPI program?
...ernative would be having each process write debug output to a separate log file, but this doesn't really give the same freedom as a debugger.
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