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Iterate over Python list with clear code - rewriting functions

I've followed a tutorial to write a Flask REST API and have a special request about a Python code.
The offered code is following:
# data list is where my objects are stored
def put_one(name):
list_by_id = [list for list in data_list if list['name'] == name]
list_by_id[0]['name'] = [new_name]
print({'list_by_id' : list_by_id[0]})
It works, which is nice, and even though I understand what line 2 is doing, I would like to rewrite it in a way that it's clear how the function iterates over the different lists. I already have an approach but it returns Key Error: 0
def put(name):
list_by_id = []
list = []
for list in data_list:
if(list['name'] == name):
list_by_id = list
list_by_id[0]['name'] = request.json['name']
return jsonify({'list_by_id' : list_by_id[0]})
My goal with this is also to be able to put other elements, that don't necessarily have the type 'name'. If I get to rewrite the function in an other way I'll be more likely to adapt it to my needs.
I've looked for tools to convert one way of coding into the other and answers in forums before coming here and couldn't find it.

It may not be beatiful code, but it gets the job done:
def put(value):
for i in range(len(data_list)):
key_list = list(data_list[i].keys())
if data_list[i][key_list[0]] == value:
print(f"old value: {key_list[0], data_list[i][key_list[0]]}")
data_list[i][key_list[0]] = request.json[test_key]
print(f"new value: {key_list[0], data_list[i][key_list[0]]}")
break
Now it doesn't matter what the key value is, with this iteration the method will only change the value when it finds in the data_list. Before the code breaked at every iteration cause the keys were different and they played a role.

how to iterate array of dictionary without loop using django?

This my scenario. I have 30 records in the array of dictionary in django. So, I tried to iterate it's working fine. but it takes around one minute. How to reduce iteration time. I tried map function but it's not working. How to fix this and I will share my example code.
Example Code
def find_places():
data = [{'a':1},{'a':2},{'a':3},{'a':4},{'a':5},{'a':6},{'a':7},{'a':8}]
places =[]
for p in range(1,len(data)):
a = p.a
try:
s1 = sample.object.filter(a=a)
except:
s1 = sample(a=a)
s1.save()
plac={id:s1.id,
a:s1.a}
places.append(plac)
return places
find_places()
I need an efficient way to iterate the array of objects in python without a loop.

You can filter outside the loop and run get_or_create instead of reverting to an object creation if the filter doesn't match.
data_a = [d.a for d in data]
samples = sample.objects.filter(a__in=data_a)
places = []
for a in data_a:
s1, created = samples.get_or_create(
a=a
)
place = {id: s1.id, a:s1.a}
places.append(place)

You can try this:
You can create a list hen save it at once, try this:
def find_places():
data = [{'a':1},{'a':2},{'a':3},{'a':4},{'a':5},{'a':6},{'a':7},{'a':8}]
places =[]
lst = []
for p in data:
a = p['a']
lst.append(a) # store it at once
Then try to store it into database. You can search: How to store a list into Model in Django.
I only made changes to loop of the code, if database side also fails you can let me know.

My CSV files are not being assigned to the correct Key in a dictionary

def read_prices(tikrList):
#read each file and get the price list dictionary
def getPriceDict():
priceDict = {}
TLL = len(tikrList)
for x in range(0,TLL):
with open(tikrList[x] + '.csv','r') as csvFile:
csvReader = csv.reader(csvFile)
for column in csvReader:
priceDict[column[0]] = float(column[1])
return priceDict
#populate the final dictionary with the price dictionary from the previous function
def popDict():
combDict = {}
TLL = len(tikrList)
for x in range(0,TLL):
for y in tikrList:
combDict[y] = getPriceDict()
return combDict
return(popDict())
print(read_prices(['GOOG','XOM','FB']))
What is wrong with the code is that when I return the final dictionary the key for GOOG,XOM,FB is represnting the values for the FB dictionary only.
As you can see with this output:
{'GOOG': {'2015-12-31': 104.660004, '2015-12-30': 106.220001},
'XOM': {'2015-12-31': 104.660004, '2015-12-30': 106.220001},
'FB': {'2015-12-31': 104.660004, '2015-12-30': 106.220001}
I have 3 different CSV files but all of them are just reading the CSV file for FB.
I want to apologize ahead of time if my code is not easy to read or doesn't make sense. I think there is an issue with storing the values and returning the priceDict in the getPriceDict function but I cant seem to figure it out.
Any help is appreciated, thank you!

Since this is classwork I won't provide a solution but I'll point a few things out.
You have defined three functions - two are defined inside the third. While structuring functions like that can make sense for some problems/solutions I don't see any benefit in your solution. It seems to make it more complicated.
The two inner functions don't have any parameters, you might want to refactor them so that when they are called you pass them the information they need. One advantage of a function is to encapsulate an idea/process into a self-contained code block that doesn't rely on resources external to itself. This makes it easy to test so you know that the function works and you can concentrate on other parts of the code.
This piece of your code doesn't make much sense - it never uses x from the outer loop:
...
for x in range(0,TLL):
for y in tikrList:
combDict[y] = getPriceDict()
When you iterate over a list the iteration will stop after the last item and it will iterate over the items themselves - no need to iterate over numbers to access the items: don't do for i in range(thelist): print(thelist[i])
>>> tikrList = ['GOOG','XOM','FB']
>>> for name in tikrList:
... print(name)
GOOG
XOM
FB
>>>
When you read through a tutorial or the documentation, don't just look at the examples - read and understand the text .

How to iterate a command (loop) through files in a list in Python

I'm new in Python. I'm trying to a write a brief script. I want to run a loop in which I have to read many files and for each file run a command.In particular, I want to do a calculation throught the the two rows of every file and return an output whith a name which is refered to the relative file.
I was able to load the files in a list ('work'). I tried to write the second single loop for the calculation that I have to do whith one of the file in the list and it runs correctly. THe problem is that I'm not able to iterate it over all the files and obtain each 'integr' value from the relative file.
Let me show what I tried to do:
import numpy as np
#I'm loading the files that contain the values whith which I want to do my calculation in a loop
work = {}
for i in range(0,100):
work[i] = np.loadtxt('work{}.txt'.format(i), float).T
#Now I'm trying to write a double loop in which I want to iterate the second loop (the calculation) over the files (that don't have the same length) in the list
integr = 0
for k in work:
for i in range(1, len(k[1,:])):
integr = integr + k[1,i]*(k[0,i] - k[0,i-1])
#I would like to print every 'integr' which come from the calculation over each file
print(integr)
When I try to run this, I obtain this message error:
Traceback (most recent call last):
File "lavoro.py", line 11, in <module>
for i in range(1, len(k[1,:])):
TypeError: 'int' object has no attribute '__getitem__'
Thank you in advance.

I am a bit guessing, but if I understood correctly, you want work to be a list and not a dictionary. Or maybe you don't want it, but surely you can use a list instead of a dictionary, given the context.
This is how you can create your work list:
work = []
for i in range(0,100):
work.append(np.loadtxt('work{}.txt'.format(i), float).T)
Or using the equivalent list comprehension of the above loop (usually the list comprehension is faster):
work = [np.loadtxt('work{}.txt'.format(i), float).T for i in range(100)]
Now you can loop over the work list to do your calculations (I assume they are correct, no way for me to check this):
for k in work:
integr = 0
for i in range(1, len(k[1,:])):
integr = integr + k[1,i]*(k[0,i] - k[0,i-1])
Note that I moved integr = 0 inside the loop, so that is reinitalized to 0 for each file, otherwise each inner loop will add to the result of the previous inner loops.
However if that was the desided behaviour, move integr = 0 outside the loop as your original code.

Guessing from the context you wanted:
for k in work.values():
iterating over dictionary produces only keys, not values.

Help with Excel, Python and XLRD

Relatively new to programming hence why I've chosen to use python to learn.
At the moment I'm attempting to read a list of Usernames, passwords from an Excel Spreadsheet with XLRD and use them to login to something. Then back out and go to the next line. Log in etc and keep going.
Here is a snippit of the code:
import xlrd
wb = xlrd.open_workbook('test_spreadsheet.xls')
# Load XLRD Excel Reader
sheetname = wb.sheet_names() #Read for XCL Sheet names
sh1 = wb.sheet_by_index(0) #Login
def readRows():
for rownum in range(sh1.nrows):
rows = sh1.row_values(rownum)
userNm = rows[4]
Password = rows[5]
supID = rows[6]
print userNm, Password, supID
print readRows()
I've gotten the variables out and it reads all of them in one shot, here is where my lack of programming skills come in to play. I know I need to iterate through these and do something with them but Im kind of lost on what is the best practice. Any insight would be great.
Thank you again

couple of pointers:
i'd suggest you not print your function with no return value, instead just call it, or return something to print.
def readRows():
for rownum in range(sh1.nrows):
rows = sh1.row_values(rownum)
userNm = rows[4]
Password = rows[5]
supID = rows[6]
print userNm, Password, supID
readRows()
or looking at the docs you can take a slice from the row_values:
row_values(rowx, start_colx=0,
end_colx=None) [#]
Returns a slice of the values of the cells in the given row.
because you just want rows with index 4 - 6:
def readRows():
# using list comprehension
return [ sh1.row_values(idx, 4, 6) for idx in range(sh1.nrows) ]
print readRows()
using the second method you get a list return value from your function, you can use this function to set a variable with all of your data you read from the excel file. The list is actually a list of lists containing your row values.
L1 = readRows()
for row in L1:
print row[0], row[1], row[2]
After you have your data, you are able to manipulate it by iterating through the list, much like for the print example above.
def login(name, password, id):
# do stuff with name password and id passed into method
...
for row in L1:
login(row)
you may also want to look into different data structures for storing your data. If you need to find a user by name using a dictionary is probably your best bet:
def readRows():
rows = [ sh1.row_values(idx, 4, 6) for idx in range(sh1.nrows) ]
# using list comprehension
return dict([ [row[4], (row[5], row[6])] for row in rows ])
D1 = readRows()
print D['Bob']
('sdfadfadf',23)
import pprint
pprint.pprint(D1)
{'Bob': ('sdafdfadf',23),
'Cat': ('asdfa',24),
'Dog': ('fadfasdf',24)}
one thing to note is that dictionary values returned arbitrarily ordered in python.

I'm not sure if you are intent on using xlrd, but you may want to check out PyWorkbooks (note, I am the writter of PyWorkbooks :D)
from PyWorkbooks.ExWorkbook import ExWorkbook
B = ExWorkbook()
B.change_sheet(0)
# Note: it might be B[:1000, 3:6]. I can't remember if xlrd uses pythonic addressing (0 is first row)
data = B[:1000,4:7] # gets a generator, the '1000' is arbitrarily large.
def readRows()
while True:
try:
userNm, Password, supID = data.next() # you could also do data[0]
print userNm, Password, supID
if usrNm == None: break # when there is no more data it stops
except IndexError:
print 'list too long'
readRows()
You will find that this is significantly faster (and easier I hope) than anything you would have done. Your method will get an entire row, which could be a thousand elements long. I have written this to retrieve data as fast as possible (and included support for such things as numpy).
In your case, speed probably isn't as important. But in the future, it might be :D
Check it out. Documentation is available with the program for newbie users.
http://sourceforge.net/projects/pyworkbooks/

Seems to be good. With one remark: you should replace "rows" by "cells" because you actually read values from cells in every single row