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How do I get the row count of a pandas DataFrame?
...eturn non-NaN counts for each column:
df.count()
A 5
B 3
dtype: int64
For Series, use Series.count to similar effect:
s.count()
# 3
Group-wise Row Count: GroupBy.size
For DataFrames, use DataFrameGroupBy.size to count the number of rows per group.
df.groupby('A').size()
A
a 2
b ...
dropping infinite values from dataframes in pandas?
...
Use (fast and simple):
df = df[np.isfinite(df).all(1)]
This answer is based on DougR's answer in an other question.
Here an example code:
import pandas as pd
import numpy as np
df=pd.DataFrame([1,2,3,np.nan,4,np.inf,5,-np.inf,6])
print('Input:\n',df,sep='')
df = df[np.isfinite(df).all(1)]
prin...
Why does installing Nokogiri on Mac OS fail with libiconv is missing?
...or unsupported file format which is not the architecture being linked (x86_64) for architecture x86_64
Uhh, what? After a lot of googling, I came across this miracle post: http://www.refresherate.com/2010/01/08/fixing-ld-warning-in-usrlocalliblibz-dylib-file-is-not-of-required-architecture/
Appar...
Groovy / grails how to determine a data type?
...
instanceof is great for filtering based on interface.
– cdeszaq
Mar 12 '13 at 13:15
...
Storing SHA1 hash values in MySQL
...ch occured when I wanted to store the result of a SHA1 hash in a MySQL database:
7 Answers
...
Detect application heap size in Android
... to 32:
maxMemory: 33554432
getMemoryClass: 32
With VM Heap Size set to 64:
maxMemory: 67108864
getMemoryClass: 32
In addition to the above, I tested on a Novo7 Paladin tablet running Ice Cream Sandwich.
This was essentially a stock version of ICS, except that I've rooted the tablet through...
Android emulator and virtualbox cannot run at same time
...run with CPU/ABI x86/x86_64 is a lot faster, but uses the same KVM (Kernel-based Virtual Machine) as VitualBox. Creating an emulator with another CPU, like arm64, will not conflict with VirtualBox, but emulator is a lot slower.
– jayeffkay
Jan 18 '17 at 13:24
...
Pandas - Get first row value of a given column
...ecommended) and df_test.iloc[0]['Btime']:
DataFrames store data in column-based blocks (where each block has a single
dtype). If you select by column first, a view can be returned (which is
quicker than returning a copy) and the original dtype is preserved. In contrast,
if you select by row first, ...
What is the MySQL VARCHAR max size?
...
As per the online docs, there is a 64K row limit and you can work out the row size by using:
row length = 1
+ (sum of column lengths)
+ (number of NULL columns + delete_flag + 7)/8
+ (number of variable-length columns)
...
Excel RTD(Excel Real-Time Data)实时刷新数据技术 - C/C++ - 清泛网 - 专注C/C++及内核技术
...题时调用ServerStart方法，该方法会在成功时返回 1，并在失败时返回负值或 0。这个方法在随后应用其他RTD函数时不会再次被调用。
ConnectData(TopicID, Strings, GetNewValues)
其中，TopcID 唯一标识这个函数在Excel中的一个应用，即使复制...