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Rename specific column(s) in pandas
...lse x, axis=1)
Index.str.replace
Similar to replace method of strings in python, pandas Index and Series (object dtype only) define a ("vectorized") str.replace method for string and regex-based replacement.
df.columns = df.columns.str.replace('gdp', 'log(gdp)')
df
y log(gdp) cap
0 x ...
How can I parse a CSV string with JavaScript, which contains comma in data?
... are first presented in native regular expressions syntax (expressed using Python's handy r'''...''' raw-multi-line-string syntax).
First here is a regular expression which validates that a CVS string meets the above requirements:
Regular expression to validate a "CSV string":
re_valid = r"""
# Vali...
How to create the most compact mapping n → isprime(n) up to a limit N?
...orithm I usually implement (easy to understand and code) is as follows (in Python):
def isprime(n):
"""Returns True if n is prime."""
if n == 2:
return True
if n == 3:
return True
if n % 2 == 0:
return False
if n % 3 == 0:
return False
i = 5
...
Is it possible to specify your own distance function using scikit-learn K-Means Clustering?
... enough);
in particular, what are your N, dim, k, metric ?
#!/usr/bin/env python
# kmeans.py using any of the 20-odd metrics in scipy.spatial.distance
# kmeanssample 2 pass, first sample sqrt(N)
from __future__ import division
import random
import numpy as np
from scipy.spatial.distance import cdi...
Can I mask an input text in a bat file?
... the command line. For example, you can replace the cscript section with: 'python -c "from getpass import getpass; pwd = getpass(); print pwd;"'
– Cerin
Jul 30 '10 at 17:15
1
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Shortest distance between a point and a line segment
...to be (that's why I made this).
Implementation of theory by Paul Bourke.
Python:
def dist(x1, y1, x2, y2, x3, y3): # x3,y3 is the point
px = x2-x1
py = y2-y1
norm = px*px + py*py
u = ((x3 - x1) * px + (y3 - y1) * py) / float(norm)
if u > 1:
u = 1
elif u <...
How to check whether a pandas DataFrame is empty?
...
In Python, try/except is cheap and if is expensive. Python is neither Java nor C; here it's Easier to Ask Forgiveness than Permission
– Nick Marinakis
Apr 14 at 1:26
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What does this square bracket and parenthesis bracket notation mean [first1,last1)?
... programming languages tends to be zero-based, such as C, C++, Javascript, Python, while other languages such as Mathematica, Fortran, Pascal are one-based.
These differences can lead to subtle fence post errors, aka, off-by-one bugs when implementing Mathematical algorithms such as for-loops.
...
How to read a .xlsx file using the pandas Library in iPython?
I want to read a .xlsx file using the Pandas Library of python and port the data to a postgreSQL table.
6 Answers
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Please explain some of Paul Graham's points on Lisp
...about language fundamentals. You wouldn't hear a similar claim of Java, C, Python, Perl, Haskell, etc. as a good beginner's project!
– Matt Curtis
Apr 26 '10 at 0:57
9
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