Category: Python Answers

Sometimes, we want to replace multiple characters in a string with Python.

In this article, we’ll look at how to replace multiple characters in a string with Python.

How to replace multiple characters in a string with Python?

To replace multiple characters in a string with Python, we can use the string translate and str.maketrans methods.

For instance, we write

s = "abc&def#ghi"
print(s.translate(str.maketrans({'&': '\&', '#': '\#'})))

to call str.maketrans with a dict that has the keys of the substrings to look for.

And we replace them with the strings in the values,

Then we call s.translate with the object returned by maketrans to do the replacement of the values and return a new string with the replacement done.

Conclusion

To replace multiple characters in a string with Python, we can use the string translate and str.maketrans methods.

Sometimes, we want to fix Import error: No module name urllib2 with Python.

In this article, we’ll look at how to fix Import error: No module name urllib2 with Python.

How to fix Import error: No module name urllib2 with Python?

To fix Import error: No module name urllib2 with Python, we can use the right module of urllib.

For instance, we write

from urllib.request import urlopen
html = urlopen("http://www.google.com/").read()
print(html)

to import urlopen from the urllib.request module.

Then we call urlopen to open http://www.google.com/ and get the response with read.

Conclusion

To fix Import error: No module name urllib2 with Python, we can use the right module of urllib.

Sometimes, we want to urlencode a querystring in Python.

In this article, we’ll look at how to urlencode a querystring in Python.

How to urlencode a querystring in Python?

To urlencode a querystring in Python, we can use the urllib.parse.quote_plus method.

For instance, we wite

import urllib.parse

safe_string = urllib.parse.quote_plus('string_of_characters_like_these:$#@=?%^Q^$')

to call quote_plus with a string that we want to urlencode.

Conclusion

To urlencode a querystring in Python, we can use the urllib.parse.quote_plus method.

Sometimes, we want to read .mat files in Python.

In this article, we’ll look at how to read .mat files in Python.

How to read .mat files in Python?

To read .mat files in Python, we can use the SciPy loadmat method.

For instance, we write

import scipy.io

mat = scipy.io.loadmat('file.mat')

to call scipy.io.loadmat to read the file.mat MATLAB file.

Conclusion

To read .mat files in Python, we can use the SciPy loadmat method.

Sometimes, we want to remove pandas rows with duplicate indices with Python.

In this article, we’ll look at how to remove pandas rows with duplicate indices with Python.

How to remove pandas rows with duplicate indices with Python?

To remove pandas rows with duplicate indices with Python, we can use the index.duplicated method.

For instance, we write

df = df[~df.index.duplicated(keep='first')]

to call df.index.duplicated where df is a Pandas data frame.

We call it with the keep argument set to 'first' and add ~ to keep the first instance of the item and remove the duplicates.

And then we put that in the square brackets to get a data frame without the entries with duplicate indices and assign that to df.

Conclusion

To remove pandas rows with duplicate indices with Python, we can use the index.duplicated method.