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How to check if a file exists in Go?
... function solely intended to check if a file exists or not (like Python's os.path.exists ). What is the idiomatic way to do it?
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How get integer value from a enum in Rails?
...lass to access the integer value for that instance:
my_model = Model.find(123)
Model.sale_infos[my_model.sale_info] # Returns the integer value
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How can I safely create a nested directory?
What is the most elegant way to check if the directory a file is going to be written to exists, and if not, create the directory using Python? Here is what I tried:
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What does [object Object] mean?
...answered Aug 21 '14 at 6:25
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How to find the operating system version using JavaScript?
How can I find the OS name and OS version using JavaScript?
13 Answers
13
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How to access environment variable values?
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Environment variables are accessed through os.environ
import os
print(os.environ['HOME'])
Or you can see a list of all the environment variables using:
os.environ
As sometimes you might need to see a complete list!
# using get will return `None` if a key is not...
Batch file: Find if substring is in string (not in a file)
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When this is run in CMD.EXE, we get:
C:\DemoDev>y pqrs "abc def pqr 123"
got one - pattern not found
C:\DemoDev>y pqr "abc def pqr 123"
got zero - found pattern
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Test if characters are in a string
...# Correct
> grepl("1+2", "1+2", fixed=TRUE)
[1] TRUE
> grepl("1+2", "123+456", fixed=TRUE)
[1] FALSE
# Incorrect
> grepl("1+2", "1+2")
[1] FALSE
> grepl("1+2", "123+456")
[1] TRUE
Interpretation
grep is named after the linux executable, which is itself an acronym of "Global Regular...
Python list directory, subdirectory, and files
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Use os.path.join to concatenate the directory and file name:
for path, subdirs, files in os.walk(root):
for name in files:
print os.path.join(path, name)
Note the usage of path and not root in the concatenation, sinc...
How do I check whether a file exists without exceptions?
...open it.
If you're not planning to open the file immediately, you can use os.path.isfile
Return True if path is an existing regular file. This follows symbolic links, so both islink() and isfile() can be true for the same path.
import os.path
os.path.isfile(fname)
if you need to be sure it...