Found 33676 Articles for Programming

Python: Can not understand why I am getting the error: Can not concatenate 'int' and 'str' object

Ayush Gupta
Updated on 12-Mar-2020 12:31:58

118 Views

This error is coming because the interpreter is replacing the %d with i and then trying to add 1 to a str, ie, adding a str and an int. In order to correct this, just surround the i+1 in parentheses. exampleprint("\ Num %d" % (i+1))

Python: Cannot understand why the error - cannot concatenate 'str' and 'int' object ?

Jayashree
Updated on 13-Mar-2020 05:15:39

216 Views

This can be corrected by putting n+1 in brackets i.e. (n+1)for num in range(5):     print ("%d" % (num+1))Using %d casts the object following % to string. Since a string object can't be concatnated with a number (1 in this case) interpreter displays typeerror.

How to create a lambda inside a Python loop?

Lakshmi Srinivas
Updated on 05-Mar-2020 09:54:01

1K+ Views

You can create a list of lambdas in a python loop using the following syntax −Syntaxdef square(x): return lambda : x*x listOfLambdas = [square(i) for i in [1,2,3,4,5]] for f in listOfLambdas: print f()OutputThis will give the output −1 4 9 16 25You can also achieve this using a functional programming construct called currying. examplelistOfLambdas = [lambda i=i: i*i for i in range(1, 6)] for f in listOfLambdas:    print f()OutputThis will give the output −1 4 9 16 25

How do I loop through a JSON file with multiple keys/sub-keys in Python?

Sravani S
Updated on 05-Mar-2020 08:14:19

15K+ Views

You can parse JSON files using the json module in Python. This module parses the json and puts it in a dict. You can then get the values from this like a normal dict. For example, if you have a json with the following content −{    "id": "file",    "value": "File",    "popup": {       "menuitem": [          {"value": "New", "onclick": "CreateNewDoc()"},          {"value": "Open", "onclick": "OpenDoc()"},          {"value": "Close", "onclick": "CloseDoc()"}       ]    } }ExampleYou can load it in your python program and loop ... Read More

How to execute Python multi-line statements in the one-line at command-line?

Samual Sam
Updated on 05-Mar-2020 08:08:02

2K+ Views

There are multiple ways in which you can use multiline statements in the command line in python. For example, bash supports multiline statements, which you can use like −Example$ python -c ' > a = True > if a: > print("a is true") > 'OutputThis will give the output −a is trueIf you prefer to have the python statement in a single line, you can use the newline between the commands. example$ python -c $'a = Trueif a: print("a is true");'OutputThis will give the output −a is true

How to loop through multiple lists using Python?

V Jyothi
Updated on 05-Mar-2020 08:06:15

588 Views

The most straightforward way seems to use an external iterator to keep track. Note that this answer considers that you're looping on same sized lists. examplea = [10, 12, 14, 16, 18] b = [10, 8, 6, 4, 2] for i in range(len(a)):    print(a[i] + b[i])OutputThis will give the output −20 20 20 20 20ExampleYou can also use the zip method that stops when the shorter of a or b stops.a = [10, 12, 14, 16, 18] b = [10, 8, 6] for (A, B) in zip(a, b):    print(A + B)OutputThis will give the output −20 20 20

compareTo() definition mistake?

Pythonista
Updated on 30-Jul-2019 22:30:22

184 Views

The example works correctly. The compareTo() method is called by a string object and takes another string object as argument. The return value is integer and is difference in Unicode values of characters of respective strings when they are not equal. The value can be -ve, 0 or +ve.

How to use if...else statement at the command line in Python?

Priya Pallavi
Updated on 17-Jun-2020 12:03:59

1K+ Views

There are multiple ways in which you can use if else construct in the command line in python. For example, bash supports multiline statements, which you can use like:$ python -c ' > a = True > if a: > print("a is true") > 'This will give the output:a is trueIf you prefer to have the python statement in a single line, you can use the newline between the commands. For example,$ python -c $'a = Trueif a: print("a is true");'This will give the output:a is true

What are common programming errors or 'gotchas' in Python?

Nikitha N
Updated on 05-Mar-2020 07:58:40

198 Views

Here are some of the most common python programming mistakes/gotchas that programmers commit:Scope name lookups: Python follows scoping rules in order of LEGB(Local, Enclosing, Global, Built-in). Since python has no strict type binding, programmers can reassociate an outer scope variable to another value that might be used in the outer scope later but is now replaced by some other value.Not differentiating between is and =: The is an operator in python checks if both objects refer to the same memory address. The == operator executes __eq__ function which might check for equality differently for different classes.Modifying a list while iterating ... Read More

How to compare two variables in an if statement using Python?

karthikeya Boyini
Updated on 05-Mar-2020 07:52:57

6K+ Views

You can compare 2 variables in an if statement using the == operator. examplea = 10 b = 15 if a == b:    print("Equal") else:    print("Not equal")OutputThis will give the output −Not EqualYou can also use the is the operator. examplea = "Hello" b = a if a is b:    print("Equal") else:    print("Not equal")OutputThis will give the output −EqualNote that is will return True if two variables point to the same object, == if the objects referred to by the variables are equal.

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