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Can we write our own iterator in Java?
...rray of Strings
String[] languages = new String[]{"C", "C++", "Java", "Python", "Scala"};
// create your list and hold the values using the same list implementation.
SOList<String> languagesList = new SOList<String>(languages);
System.out.println("");
// Since our c...
get list from pandas dataframe column
...u pull them out, which you can then call x.tolist() on to turn them into a Python list. Alternatively you cast it with list(x).
import pandas as pd
data_dict = {'one': pd.Series([1, 2, 3], index=['a', 'b', 'c']),
'two': pd.Series([1, 2, 3, 4], index=['a', 'b', 'c', 'd'])}
df = pd.Data...
add a string prefix to each value in a string column using Pandas
...lso yields the desired output:
col
0 stra
1 str0
If you are using Python 3.6+, you can also use f-strings:
df['col'] = df['col'].apply(lambda x: f"str{x}")
yielding the same output.
The f-string version is almost as fast as @RomanPekar's solution (python 3.6.4):
df = pd.DataFrame({'col...
What's the recommended approach to resetting migration history using Django South?
... are taking too long, this worked for me.
rm <app-dir>/migrations/*
python manage.py schemamigration <app-name> --initial
python manage.py migrate <app-name> 0001 --fake --delete-ghost-migrations
Don't forget to manually restore any dependencies on other apps by adding lines li...
When should I use @classmethod and when def method(self)?
...atic method of java or C++. ( static method is a general term I guess ;) )
Python also has @staticmethod. and difference between classmethod and staticmethod is whether you can
access to class or static variable using argument or classname itself.
class TestMethod(object):
cls_var = 1
@clas...
differentiate null=True, blank=True in django
...: CharFields can get saved as NULL in the database (translating to None in Python) if you set null=True. The docs even say to avoid setting null=True because it allows two different kinds of "blanky" values. I just tested this behaviour with Django 1.8/MySQL 5.6
– Edward D'Souz...
How to organize large R programs?
...s top-level namespace (the one that ls() shows).
I was trying to simulate Python's system, where every file is a module. That would be better to have, but this seems OK.
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improve this answe...
Inserting a Link to a Webpage in an IPython Notebook
...
In case it is not a markdown cell, that is with what I went:
from IPython.core.display import display, HTML
display(HTML("""<a href="https://google.at">text</a>"""))
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imp...
How can I get the sha1 hash of a string in node.js?
...S is hashing the UTF-8 representation of the string. Other languages (like Python, PHP or PERL...) are hashing the byte string.
We can add binary argument to use the byte string.
const crypto = require("crypto");
function sha1(data) {
return crypto.createHash("sha1").update(data, "binary").dig...
What is a lambda (function)?
... nice way to write closures. With that power you can do things like this.
Python
def adder(x):
return lambda y: x + y
add5 = adder(5)
add5(1)
6
As you can see from the snippet of Python, the function adder takes in an argument x, and returns an anonymous function, or lambda, that takes anoth...