I"ve got a dataframe called data. How would I rename the only one column header? For example gdp to log(gdp)?
data =
y gdp cap
0 1 2 5
1 2 3 9
2 8 7 2
3 3 4 7
4 6 7 7
5 4 8 3
6 8 2 8
7 9 9 10
8 6 6 4
9 10 10 7
Rename specific column(s) in pandas log: Questions
Python"s equivalent of && (logical-and) in an if-statement
5 answers
Here"s my code:
def front_back(a, b):
# +++your code here+++
if len(a) % 2 == 0 && len(b) % 2 == 0:
return a[:(len(a)/2)] + b[:(len(b)/2)] + a[(len(a)/2):] + b[(len(b)/2):]
else:
#todo! Not yet done. :P
return
I"m getting an error in the IF conditional.
What am I doing wrong?
Answer #1
You would want and instead of &&.
Answer #2
Python uses and and or conditionals.
i.e.
if foo == "abc" and bar == "bac" or zoo == "123":
# do something
How do you get the logical xor of two variables in Python?
5 answers
How do you get the logical xor of two variables in Python?
For example, I have two variables that I expect to be strings. I want to test that only one of them contains a True value (is not None or the empty string):
str1 = raw_input("Enter string one:")
str2 = raw_input("Enter string two:")
if logical_xor(str1, str2):
print "ok"
else:
print "bad"
The ^ operator seems to be bitwise, and not defined on all objects:
>>> 1 ^ 1
0
>>> 2 ^ 1
3
>>> "abc" ^ ""
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for ^: "str" and "str"
Answer #1
If you"re already normalizing the inputs to booleans, then != is xor.
bool(a) != bool(b)
Rename specific column(s) in pandas rename: Questions
Rename a dictionary key
5 answers
Is there a way to rename a dictionary key, without reassigning its value to a new name and removing the old name key; and without iterating through dict key/value?
In case of OrderedDict, do the same, while keeping that key"s position.
Answer #1
For a regular dict, you can use:
mydict[k_new] = mydict.pop(k_old)
This will move the item to the end of the dict, unless k_new was already existing in which case it will overwrite the value in-place.
For a Python 3.7+ dict where you additionally want to preserve the ordering, the simplest is to rebuild an entirely new instance. For example, renaming key 2 to "two":
>>> d = {0:0, 1:1, 2:2, 3:3}
>>> {"two" if k == 2 else k:v for k,v in d.items()}
{0: 0, 1: 1, "two": 2, 3: 3}
The same is true for an OrderedDict, where you can"t use dict comprehension syntax, but you can use a generator expression:
OrderedDict((k_new if k == k_old else k, v) for k, v in od.items())
Modifying the key itself, as the question asks for, is impractical because keys are hashable which usually implies they"re immutable and can"t be modified.
How to rename a file using Python
5 answers
I want to change a.txt to b.kml.
Answer #1
Use os.rename:
import os
os.rename("a.txt", "b.kml")
Rename multiple files in a directory in Python
5 answers
I"m trying to rename some files in a directory using Python.
Say I have a file called CHEESE_CHEESE_TYPE.*** and want to remove CHEESE_ so my resulting filename would be CHEESE_TYPE
I"m trying to use the os.path.split but it"s not working properly. I have also considered using string manipulations, but have not been successful with that either.
Answer #1
Use os.rename(src, dst) to rename or move a file or a directory.
$ ls
cheese_cheese_type.bar cheese_cheese_type.foo
$ python
>>> import os
>>> for filename in os.listdir("."):
... if filename.startswith("cheese_"):
... os.rename(filename, filename[7:])
...
>>>
$ ls
cheese_type.bar cheese_type.foo
