‘numpy.ndarray’ object has no attribute ‘index’
First of all, index is a list method. Here v is a numpy array and you need to do the following: Get the elements using these indices: Verify using assert:
python
Best way to return multiple values from a function? [closed]
Named tuples were added in 2.6 for this purpose. Also see os.stat for a similar builtin example. In recent versions of Python 3 (3.6+, I think), the new typing library got the NamedTuple class to make named tuples easier to create and more powerful. Inheriting from typing.NamedTuple lets you use docstrings, default values, and type annotations. Example (From the docs):
The difference between comparison to np.nan and isnull()
np.nan is not comparable to np.nan… directly. While Could also do examplesFilters nothing because nothing is equal to np.nan Filters out the null Use odd comparison behavior to get what we want anyway. If np.nan != np.nan is True then Just dropna
Accessing the index in ‘for’ loops?
Using an additional state variable, such as an index variable (which you would normally use in languages such as C or PHP), is considered non-pythonic. The better option is to use the built-in function enumerate(), available in both Python 2 and 3:
What is the necessity of plt.figure() in matplotlib?
The purpose of using plt.figure() is to create a figure object. The whole figure is regarded as the figure object. It is necessary to explicitly use plt.figure() when we want to tweak the size of the figure and when we want to add multiple Axes objects in a single figure. Parts of a Figure
Pip freeze vs. pip list
When you are using a virtualenv, you can specify a requirements.txt file to install all the dependencies. A typical usage: The packages need to be in a specific format for pip to understand, which is That is the “requirements format”. Here, django==1.4.2 implies install django version 1.4.2 (even though the latest is 1.6.x). If you … Read more
How do I list all files of a directory?
How can I list all files of a directory in Python and add them to a list?
ImportError: No module named matplotlib.pyplot
You have two pythons installed on your machine, one is the standard python that comes with Mac OSX and the second is the one you installed with ports (this is the one that has matplotlib installed in its library, the one that comes with macosx does not). Is the standard mac python and since it … Read more
Converting string into datetime
datetime.strptime is the main routine for parsing strings into datetimes. It can handle all sorts of formats, with the format determined by a format string you give it: The resulting datetime object is timezone-naive. Links: Python documentation for strptime: Python 2, Python 3 Python documentation for strptime/strftime format strings: Python 2, Python 3 strftime.org is … Read more
ValueError: could not convert string to float: id
Obviously some of your lines don’t have valid float data, specifically some line have text id which can’t be converted to float. When you try it in interactive prompt you are trying only first line, so best way is to print the line where you are getting this error and you will know the wrong … Read more