nan

I have a DataFrame which looks like this: one | two a | 2 | 5 b | 3 | 6 NaN | 0 | 0 How do I replace the NaN in the index with a string, say "No label"? I tried: df = df.replace(np.NaN, "No label") and df.index = df.index.replace(np.NaN, "No label") But got TypeError: expected string or buffer You can process the original index as a Series first and then re-assign the index: import pandas as pd import numpy as np df = pd.DataFrame({'one': [2, 3, 0], 'two': [5, 6, 0]}, index=['a', 'b', np.nan]) df.index = pd.Series(df.index).replace(np.nan, 'No label') print df Output: one two a 2 5 b 3 6 No

I would like to compile a program with gfortran and -O3 -ffast-math enabled, since it gives a nice performance boost. I was rather confused, that gfortran's isnan() catched some NaN's but not all of them. After reading Checking if a double (or float) is NaN in C++ how do I make a portable isnan/isinf function Negative NaN is not a NaN? I am under the impression that people are able to check for NaN's in C via bit-fiddling even with fast-math enabled. However, this puzzles me since fast-math can result in incorrect output for programs that depend on an exact implementation of IEEE or ISO rules

I'm trying to replace the NaN values generated in the code below to 0. I don't understand what the below won't work. It still keeps the NaN values. df_pubs=pd.read_sql("select Conference, Year, count(*) as totalPubs from publications where year>=1991 group by conference, year", db) df_pubs['Conference'] = df_pubs['Conference'].str.encode('utf-8') df_pubs = df_pubs.pivot(index='Conference', columns='Year', values='totalPubs') df_pubs.fillna(0) print df_pubs print df produces this: Year 1991 \ Conference 223 10th Anniversary Colloquium of UNU/IIST NaN 15. WLP NaN 1999 ACM SIGMOD Workshop on

Testing the isFinite function I see that NaN is an infinite number (even if it's not a number :-) ). isFinite(NaN) // returns false What's the logic behind this? Why isn't NaN finite? As Dave Newton said, NaN is not a number, and then you have to consider that it isn't finite nor infinite. The same occurs to these: NaN > 0 // false NaN < 0 // false You might want to read these articles: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/NaN https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/isFinite Because it is not a numeric value..

I'm trying to run some tests with conversions and castings of floats to other types and I want to set my float variable to different values of nan. "a bit-wise example of a IEEE floating-point standard single precision (32-bit) NaN would be: s111 1111 1axx xxxx xxxx xxxx xxxx xxxx where s is the sign (most often ignored in applications), a determines the type of NaN, and x is an extra payload (most often ignored in applications). If a = 1, it is a quiet NaN; if a is zero and the payload is nonzero, then it is a signaling NaN" Basically I want to find a way to set the payload or xxxx's of the

I have 2 nullable doubles, an expected value and an actual value (let's call them value and valueExpected). A percentage is found using 100 * (value / valueExpected). However, if valueExpected is zero, it returns NaN. Everything good so far. Now, what do I do if I need to check the value, to see if it is NaN? Normally one could use: if (!Double.IsNaN(myDouble)) But this doesn't work with nullable values (IsNaN only works with non-nullable variables). I have changed my code to do the check (valueExpected == 0), but I'm still curious - is there any way to check for a nullable NaN? Edit: When I